| serological and virological evidence of a hantaan virus-related enzootic in the united states. | the first isolation of a hantaan-related virus from a feral rat in the united states was made from a rattus norvegicus caught in new orleans. the strain, designated tchoupitoulas virus, is antigenically related to, but distinct from, the prototype strain 76-118 of hantaan virus and is the first hantaan-like virus isolated from the pancreas of a naturally infected animal. serosurveys of wild rodents from urban and rural areas in the united states indicated that hantaan-related viruses infected ur ... | 1985 | 2861241 |
| the biparental care system of the california mouse, peromyscus californicus. | most knowledge of parent-offspring relations in mammals is derived from studies of mother-infant interactions. male parental care has been less well studied. we explored maternal and paternal behavior of the california mouse, peromyscus californicus. six pairs of parents and their young were videotaped continuously for 12 hours/day, on alternate days from days 1 to 31 postpartum. males exhibit all parental activities and to the same extent as displayed by mothers, except lactation. male parental ... | 1987 | 3608423 |
| paternal behavior in the california mouse, peromyscus californicus. | | 1974 | 4847526 |
| susceptibility of peromyscus californicus californicus to infection with leishmania donovani. | | 1965 | 5886407 |
| oxytocin changes in males over the reproductive cycle in the monogamous, biparental california mouse, peromyscus californicus. | levels of plasma oxytocin in male peromyscus californicus were assessed across the reproductive cycle to provide a foundation for subsequent studies of the hormonal basis of paternal behavior and pair bonds. in experiment 1, plasma oxytocin levels were significantly higher in expectant fathers than in virgin males or fathers. plasma oxytocin increased in expectant fathers 1 day postcopulation and remained elevated for the first 15 days of gestation. plasma oxytocin declined by day 20 of gestatio ... | 1995 | 7782063 |
| the molecular mechanism underlying the "rare allele phenomenon" in a subspecific hybrid zone of the california field mouse, peromyscus californicus. | natural hybrid zones are known to have unusually high levels of novel or otherwise rare electrophoretic variants (the "rare allele phenomenon"). these variant alleles are most likely the result either of high levels of unique mutations in hybrids or of intragenic recombination between divergent alleles from the parental populations. this study uses dna sequence comparisons to determine which process has produced a rare allele of the 6-phosphogluconate dehydrogenase (6-pgd) gene in a subspecific ... | 1995 | 8587112 |
| isla vista virus: a genetically novel hantavirus of the california vole microtus californicus. | prospect hill virus (ph) was isolated from a meadow vole (microtus pennsylvanicus) in 1982, and much of its genome has been sequenced. hantaviruses of other new world microtine rodents have not been genetically characterized. we show that another microtus species (the california vole m. californicus) from the united states is host to a genetically distinct ph-like hantavirus, isla vista virus (ilv). the nucleocapsid protein of ilv differs from that of ph by 11.1% and a portion of the g2 glycopro ... | 1995 | 8847529 |
| role of small mammals in the ecology of borrelia burgdorferi in a peri-urban park in north coastal california. | the role of small mammals other than woodrats in the enzootiology of the lyme disease spirochete, borrelia burgorferi, was assessed in the peri-urban park. mammals were collected monthly from september through to april. following tick removal, the animals were tested for b. burgdorferi by culture of ear-punch biopsies. larvae and nymphs that were intermediate in morphology between ixodes spinipalpis and ixodes neotomae occurred on several species of rodents (peromyscus truei, peromyscus californ ... | 1997 | 9291589 |
| hantavirus (bunyaviridae) infections in rodents from orange and san diego counties, california. | during a screening program to determine the extent of hantavirus activity in orange and san diego counties, california, serum samples from 2,365 rodents representing nine genera and 15 species were tested for hantavirus antibodies. a reverse transcription-polymerase chain reaction on selected seropositive rodents was used to identify the specific hantavirus. rodents positive for sin nombre virus (snv) antibodies by western blot included 86 (9.1%) of 948 deer mice (peromyscus maniculatus), four ( ... | 1999 | 9988327 |
| arenavirus antibody in rodents indigenous to coastal southern california. | the purpose of this study was to extend our knowledge on the geographic and natural rodent host ranges of new world arenaviruses in california. sera from 1,094 sigmodontine and 112 murine rodents were tested for antibody against whitewater arroyo and amapari viruses. antibody was found in 55 (4.6%) of the 1,206 rodents: 4 from northwestern san diego county, 3 from los angeles county, and 48 from orange county. the antibody-positive rodents included 8 (7.8%) of 103 neotoma fuscipes, 1 (0.6%) of 1 ... | 2000 | 11289675 |
| pneumocystosis in wild small mammals from california. | cyst forms of the opportunistic fungal parasite pneumocystis carinii were found in the lungs of 34% of the desert shrew, notiosorex crawfordi (n = 59), 13% of the ornate shrew, sorex ornatus (n = 55), 6% of the dusky-footed wood rat, neotoma fuscipes (n = 16), 2.5% of the california meadow vole, microtus californicus (n = 40), and 50% of the california pocket mouse, chaetodipus californicus (n = 2) caught from southern california between february 1998 and february 2000. cysts were not found in a ... | 2001 | 11310900 |
| bear canyon virus: an arenavirus naturally associated with the california mouse (peromyscus californicus). | thirty-four rodents captured in southern california were studied to increase our knowledge of the arenaviruses indigenous to the western united states. an infectious arenavirus was isolated from 5 of 27 california mice but none of the 7 other rodents. analyses of viral nucleocapsid protein gene sequence data indicated that the isolates from the california mice are strains of a novel tacaribe serocomplex virus (proposed name "bear canyon") that is phylogenetically most closely related to whitewat ... | 2002 | 12095441 |
| variation in aromatase activity in the medial preoptic area and plasma progesterone is associated with the onset of paternal behavior. | the effects of aromatase within the brain on sexual behavior have been studied in a wide variety of species. relatively few non-mating behaviors have been considered, despite evidence that estrogen affects many social behaviors. testosterone promotes paternal behavior in california mouse (peromyscus californicus) fathers, acting primarily via aromatization to estradiol. virgin male california mice rarely exhibit paternal behavior, so we investigated whether aromatase in the brain changed with th ... | 2003 | 12869798 |
| sex differences in ultrasonic vocalizations and coordinated movement in the california mouse (peromyscus californicus). | geyer [am. zool. 21 (1981) 117] hypothesized that infant rodents increased the number of ultrasonic vocalizations when they moved in and out of the nest in order to elicit extended care from parents. we tested these hypotheses by recording ultrasonic vocalizations (usvs) and coordinated movements (locomotion and grooming) in california mouse and by recording usvs from pups before and after their parents retrieved them. in experiment 1, usvs and coordinated movements were recorded from 2 to 30 da ... | 2004 | 15222963 |
| detection and characterization of borrelia bissettii in rodents from the central california coast. | this is the first report of borrelia burgdorferi sensu lato in rodents from san luis obispo county, with most isolates obtained from a previously unreported host, neotoma lepida thomas. b. burgdorferi sensu lato was identified in seven rodent species, including the california vole, microtus californicus peale; dusky-footed woodrat, neotoma fuscipes baird; desert woodrat, neotoma lepida thomas; brush mouse, peromyscus boylii baird; california mouse, peromyscus californicus gambel; deer mouse, per ... | 2004 | 15311469 |
| effect of neonatal handling and paternal care on offspring cognitive development in the monogamous california mouse (peromyscus californicus). | in the laboratory rat and mouse, neonatal handling enhances hippocampal-dependent learning in adulthood, an effect mediated by changes in maternal behavior toward the handled young. in the present study, we examined the interaction between neonatal handling and biparental care during the early postnatal period and its effect on cognitive function in adult california mice (peromyscus californicus). we characterized the parental behavior of handled and nonhandled father-present and father-absent f ... | 2004 | 15215039 |
| vasopressin and the transmission of paternal behavior across generations in mated, cross-fostered peromyscus mice. | the role of arginine vasopressin (avp) in the nongenomic transfer of paternal behavior from fathers to offspring was examined in peromyscus. male california mice (p. californicus) exposed to fewer retrievals by white-footed mouse (p. leucopus) foster parents displayed fewer retrievals of biological offspring. in contrast, white-footed mice were retrieved equally rarely by california mouse foster parents and by biological parents and displayed no changes in pup retrieval behavior. avp-immunoreact ... | 2003 | 12802874 |
| medial preoptic lesions disrupt parental behavior in both male and female california mice (peromyscus californicus). | california mice (peromyscus californicus) are monogamous and naturally biparental, making them an ideal species in which to study the neural basis of paternal behavior. a male or female from each male-female pair was given an electrolytic or sham lesion in the medial preoptic area (mpoa), an area known to be critical for the expression of maternal behavior in rats, and retested for parental responsiveness. mpoa-lesioned males and females showed significantly longer latencies to show parental beh ... | 2002 | 12492295 |
| the importance of paternal care on pup survival and pup growth in peromyscus californicus when required to work for food. | we examined paternal care in the monogamous california mouse when wheel running was necessary to obtain food. paternal and maternal care, pup survival and feeding were compared in litters with single females (male absent) and paired females (male present) under three different foraging requirements. when wheel running was required for obtaining food (wheel contingent), the male's presence significantly increased pup survival. there were no significant effects of the male's presence on pup surviv ... | 2002 | 12429391 |
| paternal care in rodents: weakening support for hormonal regulation of the transition to behavioral fatherhood in rodent animal models of biparental care. | male rodents that are naturally paternal, like all females, must inhibit infanticide and activate direct parental behavior as they become parents. males, however, alter their behavior in the absence of parturition, postpartum ovulation and lactation, and therefore do not experience the hormone dynamics associated with such conditions. paternal males might nevertheless use the same hormones to activate pre-existing maternal behavior pathways in the brain. positive and inverse associations between ... | 2007 | 17482188 |
| entrainment impaired, masking spared: an apparent genetic abnormality that prevents circadian rhythm entrainment to 24-h lighting cycles in california mice. | lighting cycles can influence the expression of daily activity rhythms in two ways: by entraining the circadian pacemaker that normally drives this rhythm, and by directly affecting the expression of activity itself, thereby 'masking' the influence of the pacemaker. we describe a california mouse (peromyscus californicus) in which these processes are dissociated. circadian rhythms of wheel-running activity were recorded continuously while the animal was housed in a standard light/dark cycle and ... | 2002 | 12113912 |
| testosterone promotes paternal behaviour in a monogamous mammal via conversion to oestrogen. | although high testosterone (t) levels inhibit paternal behaviour in birds breeding in temperate zones many paternal mammals have a very different breeding biology, characterized by a post-partum oestrus. in species with post-partum oestrus, males may engage in t-dependent behaviours such as aggression and copulation simultaneously with paternal behaviour. we previously found that t promotes paternal behaviour in the california mouse, peromyscus californicus. we examine whether this effect is med ... | 2002 | 11958714 |
| vasopressin and aggression in cross-fostered california mice (peromyscus californicus) and white-footed mice (peromyscus leucopus). | to examine how developmental experiences alter neural pathways associated with adult social behavior, we cross-fostered pups between the more aggressive and monogamous california mouse (peromyscus californicus) and the less aggressive and polygamous white-footed mouse (p. leucopus). cross-fostered males became more like their foster parents when tested as adults. male white-footed mice became more aggressive only in an aggression test in a neutral arena, whereas the territorial california mice b ... | 2001 | 11467884 |
| paternal aggression in a biparental mouse: parallels with maternal aggression. | environmental and social factors have important effects on aggressive behaviors. we examined the effect of reproductive experience on aggression in a biparental species of mouse, peromyscus californicus. estrogens are important in mediating aggressive behavior so we also examined estrogen receptor expression and c-fos for insights into possible mechanisms of regulation. parental males were significantly more aggressive than virgin males, but no significant differences in estrogen receptor alpha ... | 2008 | 17991466 |
| testosterone, paternal behavior, and aggression in the monogamous california mouse (peromyscus californicus). | testosterone (t) mediates a trade-off, or negative correlation, between paternal behavior and aggression in several seasonally breeding avian species. however, the presence or absence of a t-mediated trade-off in mammals has received less attention. we examined the relationship between paternal behavior and territorial aggression in the biparental california mouse, peromyscus californicus. in contrast to seasonally breeding birds, t maintains paternal behavior in this year-round territorial spec ... | 2001 | 11467882 |
| type 2 diabetes mellitus, hyperlipidemia, and extremity lesions in california mice (peromyscus californicus) fed commercial mouse diets. | we characterized abnormalities of carbohydrate and lipid metabolism and determined whether those metabolic abnormalities are associated with extremity lesions in california mice (peromyscus californicus). | 2000 | 11020161 |
| adaptive significance of male parental care in a monogamous mammal. | paternal behaviour presumably evolved because male care of young was critical for offspring survival. we report field evidence indicating that paternal behaviour enhances offspring survival in a monogamous mammal, the biparental california mouse, peromyscus californicus. male removal resulted in lower offspring survival in father-absent than in father-present families. new males took up residence with widowed females, but usually after females had stopped lactating, suggesting that the importanc ... | 2000 | 10687819 |
| effects of morphine on electrically evoked contractions of the vas deferens in two congeneric rodent species differing in sperm competition intensity. | an early prediction of sperm competition theory was that males should adjust the number of sperm they deliver according to the risk of double mating and this has received empirical support in recent years. it has been suggested that adaptive regulation of sperm delivery in mammals may depend on changes in vas deferens contractility. in laboratory mice, the vas deferens is sensitive to opioid agonists and the secretion of endogenous opioid peptides can be affected by social interactions that may ... | 1999 | 10518324 |
| species differences in paternal behavior and aggression in peromyscus and their associations with vasopressin immunoreactivity and receptors. | previous comparative studies have suggested that the distribution of arginine vasopressin (avp) pathways within the brain is associated with species-typical patterns of social behavior. in the current study, male parental behavior and aggression were compared in two species of peromyscus. as predicted based on other studies, male mice from a monogamous species, the california mouse peromyscus californicus, spent more time providing parental care to offspring than males from a polygamous species, ... | 1999 | 10433884 |
| molecular evolution of two lineages of l1 (line-1) retrotransposons in the california mouse, peromyscus californicus. | the large number of l1 [long interspersed elements (line)-1] sequences found in the genome is due to the insertion of copies of the retrotransposon over evolutionary time. the majority of copies appear to be replicates of a few active, or "master" templates. a continual replacement of master templates over time gives rise to lineages distinguishable by their own unique set of shared-sequence variants. a previous analysis of l1 sequences in deer mice, peromyscus maniculatus and p. leucopus, revea ... | 1998 | 9725851 |
| paternal investment and reproductive success in the california mouse, peromyscus californicus | in species with biparental care, the degree of parental investment of each parent may be related to the size of the litter, the parental effort of the partner and the probability of future reproductive success with the same partner. these factors were examined in single females and mated pairs of peromyscus californicus who were required to 'forage' for food by running in a wheel. offspring survival and growth, parental behaviour, amount of food obtained by running in the wheel and inter-birth i ... | 1997 | 9268470 |
| male influence on interbirth interval in the monogamous california mouse when required to forage for food. | | 1997 | 9071377 |
| a neuroanatomical correlate of paternal and maternal behavior in the biparental california mouse (peromyscus californicus). | the medial preoptic area (mpoa) is important in the control of maternal behavior in rodents, and it is sexually dimorphic. this study demonstrates that the mpoa of nonparental virgin male peromyscus californicus (n = 10) is larger than that of virgin females (n = 9) because of a significantly greater number of neurons in the mpoa of virgin males. however, this sex difference in mpoa volume disappeared when males and females became parents. soma size increased significantly when females became mo ... | 1993 | 8447952 |
| responses of natural wildlife populations to air pollution. | deer mice (peromyscus californicus) trapped in areas of los angeles with high ambient air pollution are significantly more resistant to ozone (6.6 ppm for 12 h) than are mice trapped from areas with low ambient pollution (56 versus 0% survival, respectively). laboratory-born progeny of these mice show similar response patterns, indicating a genetic basis to this resistance. young mice (less than 1 yr of age) are more sensitive than older mice (15 versus 44% survival, respectively). sensitivity i ... | 1980 | 7381962 |
| "resource" exchange in the biparental california mouse (peromyscus californicus): water transfer from pups to parents. | mammalian mothers provide water to their young via milk. rodent mothers reclaim much of this water by licking the anogenital areas of their pups, stimulating reflexive urination, and consuming the pups' urine. male rodents do not provide milk (hence water) to the young, but in some species male parents may nevertheless lick their pups. we determined the amount of water transfer from pups to mothers and fathers in the biparental california mouse, peromyscus californicus, by injecting 5-, 10-, 20- ... | 1987 | 3691056 |
| prolactin and paternal behavior in the biparental california mouse, peromyscus californicus. | relatively little is known about hormonal mechanisms underlying paternal behavior in mammals. male california mice, peromyscus californicus, display extensive parental care toward their young. parental behavior of fathers, expectant fathers (males living with their pregnant partner), and virgin males was assessed in a 10-min test with a 1- to 3-day-old alien pup. few virgin males acted parental (19%) compared to fathers one day postpartum (80%) and expectant fathers (56%). plasma prolactin level ... | 1989 | 2744739 |
| effects of vaginal-cervical stimulation in seven species of muroid rodents. | six species of muroid rodents (peromyscus californicus, p. eremicus, p. gossypinus, mesocricetus auratus, rattus norvegicus and r. rattus) were given artificlal vaginal-cervical stimulation in an attempt to induce pseudopregnancy. some females of each species became pseudopregnant, but it was not clear that stimulation patterns mimicking the copulatory patterns of conspecific males were more effective than other patterns of stimulation. in the non-domesticated species (peromyscus and r. rattus) ... | 1977 | 321772 |
| weak winner effect in a less aggressive mammal: correlations with corticosterone but not testosterone. | we investigated the existence of the "winner effect" (winning an aggressive encounter following previous victories) and an associated rise in testosterone (t) in the white-footed mouse (peromyscus leucopus) which generally display low levels of aggression and territoriality. we compared the effect of previously winning three, two, one, or zero resident-intruder encounters on the likelihood of winning a subsequent aggressive encounter. although 50% of males were removed during training because of ... | 2006 | 16859719 |
| prolonged separation delays wound healing in monogamous california mice, peromyscus californicus, but not in polygynous white-footed mice, p. leucopus. | social interactions are often stressful, but under certain circumstances, they may be beneficial for health and well-being. in a previous study, wound healing was slowed after mate separation (2 days) in monogamous california mice, peromyscus californicus, but not polygynous white-footed mice, p. leucopus. although these results indicate that positive social interaction is critical for immune activity in some species, the extent to which such social effects are enduring remains unspecified. the ... | 2006 | 16616944 |
| winning fights elevates testosterone levels in california mice and enhances future ability to win fights. | the 'winner effect' has been studied in a variety of species, but only rarely in mammals. we compared effects of winning three, two, one, or zero resident-intruder encounters on the likelihood of winning a subsequent aggressive encounter in the california mouse (peromyscus californicus). during the training phase, we ensured that resident males won all encounters by staging contests with mildly sedated, smaller intruders. during the test phase, the resident male encountered an unfamiliar, more e ... | 2005 | 15979073 |
| estrogen receptor alpha and vasopressin in the paraventricular nucleus of the hypothalamus in peromyscus. | the purpose of this study was to determine the presence of estrogen receptor alpha (eralpha) and the relationship between neurons that express eralpha and produce vasopressin (avp) in the paraventricular nucleus of the hypothalamus (pvn) in new world mice of the genus peromyscus. brains were collected from male and female peromyscus californicus, peromyscus leucopus, peromyscus maniculatus, and peromyscus polionotus, and double labeled for the expression of eralpha and avp immunoreactivity (ir). ... | 2005 | 15680954 |
| social structure influences effects of pair-housing on wound healing. | chronic stress or noxious stimuli delay wound healing in humans and rodents. the effects of stress on wound healing appear to be mediated by the hypothalamic-pituitary-adrenal (hpa) axis and, in particular, increases in corticosteroids. as previously shown, positive social interaction faciltiates wound healing through suppression of corticosteroids. in the present study, we investigated the effects of pair-housing on wound healing and corticosteroid concentrations in three mouse species, the mon ... | 2005 | 15581739 |
| paternal behavior influences development of aggression and vasopressin expression in male california mouse offspring. | parental care has been demonstrated to have important effects on offspring behavioral development. california mice (peromyscus californicus) are biparental, and correlational evidence suggests that pup retrieving by fathers has important effects on the development of aggressive behavior and extra-hypothalamic vasopressin systems. we tested whether retrievals affected these systems by manipulating paternal retrieval behavior between day 15 and 21 postpartum. licking and grooming behavior affect b ... | 2006 | 16934808 |
| heritable, diet-induced hyperlipidemia in california mice (peromyscus californicus) is due to increased hepatic secretion of very low density lipoprotein triacylglycerol. | california mice (peromyscus californicus) develop type ii diabetes mellitus when fed a high-fat diet. we undertook the current studies to determine whether hyperlipidemia precedes the development of insulin resistance and to establish breeding colonies of hyperlipidemic and normolipidemic mice. for 6 wk, mice (n = 24) received a diet containing 25.8% of energy from fat. mice representing the upper and lower quartiles of serum triacylglycerol (tag) response (mean, >1000 mg/dl versus <300 mg/dl, r ... | 2006 | 17219776 |
| effect of resource availability on biparental care, and offspring neural and behavioral development in the california mouse (peromyscus californicus). | maternal care influences cognitive function in humans, primates and rodents; however, little is known about the effect of biparental care. environmental factors such as resource availability play an important role in modulating parental investment strategies with subsequent effects on the offspring. thus, we examined the interaction between foraging demand and biparental care on hippocampal development and novel object recognition in the monogamous, biparental california mouse. we characterized ... | 2007 | 17284199 |
| comparison of medial preoptic, amygdala, and nucleus accumbens lesions on parental behavior in california mice (peromyscus californicus). | we have previously shown that medial preoptic area (mpoa) lesions disrupt parental behavior in both male and female california mice (p. californicus). in the present study, we compare the effects of lesions in the mpoa, with those in the basolateral amygdala (ba) and nucleus accumbens (na) on male and female parental behaviors in the biparental california mouse. a male or multiparous female from each male-female pair was given an electrolytic or sham lesion in the mpoa, ba, or na and tested for ... | 2007 | 17610916 |
| principal host relationships and evolutionary history of the north american arenaviruses. | a previous study suggested that the genomes of the arenaviruses native to north america are a product of genetic recombination between new world arenaviruses with significantly different phylogenetic histories. the purpose of this study was to extend our knowledge of the principal host relationships and evolutionary history of the north american arenaviruses. the results of this study suggest that the large-eared woodrat (neotoma macrotis) is a principal host of bear canyon virus and that the pr ... | 2007 | 17624390 |
| rapid effects of estradiol on male aggression depend on photoperiod in reproductively non-responsive mice. | in three genuses and four species of rodents, housing in winter-like short days (8l:16d) increases male aggressive behavior. in all of these species, males undergo short-day induced regression of the reproductive system. some studies, however, suggest that the effect of photoperiod on aggression may be independent of reproductive responses. we examined the effects of photoperiod on aggressive behavior in california mice (peromyscus californicus), which do not display reproductive responsiveness ... | 2008 | 17976598 |
| experimental infection of peromyscus californicus with toxoplasma gondii. | eight female peromyscus californicus were infected with 10(2) or 10(4) toxoplasma gondii culture-derived tachyzoites (type ii or x) isolated from southern sea otters. all but 2 mice survived infection and developed antibodies to t. gondii. the 2 fatally infected mice were inoculated with 10(4) tachyzoites of the type x strain. parasite detection by immunohistochemistry (ihc) and dna amplification with 2 polymerase chain reaction (pcr) methods was compared for brain, heart, lung, liver, spleen, b ... | 2007 | 18314680 |
| testosterone release and social context: when it occurs and why. | the functions of rapid increases in testosterone seem paradoxical because they can occur in response to different social contexts, such as male-male aggressive encounters and male-female sexual encounters. this suggests that context may impact the functional consequences of changes in testosterone, whether transient or long term. many studies, including those with california mice (peromyscus californicus), have addressed these issues using manipulations and species comparisons, but many areas re ... | 2009 | 19422843 |
| promiscuity in mice is associated with increased vaginal bacterial diversity. | differences in the number of sexual partners (i.e., mating system) have the potential to exert a strong influence on the bacterial communities present in reproductive structures like the vagina. because this structure serves as a conduit for gametes, bacteria present there may have a pronounced, direct effect on host reproductive success. as a first step towards the identification of the relationship between sexual behavior and potentially pathogenic bacterial communities inhabiting vital reprod ... | 2011 | 21964973 |
| the 'home advantage' is necessary for a full winner effect and changes in post-encounter testosterone. | winning aggressive contests can both enhance future winning ability and change post-encounter hormones; however, it remains unclear if the context of a fight also influences such winner effects and hormone changes. we investigated this issue by using california mice (peromyscus californicus) to test if the effect of residency status is necessary to improve future winning ability and alter post-encounter hormones. male mice were subjected to an aggressive contest and their blood was collected 45 ... | 2009 | 19426733 |
| from here to paternity: neural correlates of the onset of paternal behavior in california mice (peromyscus californicus). | in a minority of mammalian species, including humans, fathers play a significant role in infant care. compared to maternal behavior, the neural and hormonal bases of paternal care are poorly understood. we analyzed behavioral, neuronal and neuropeptide responses towards unfamiliar pups in biparental california mice, comparing males housed with another male ("virgin males") or with a female before ("paired males") or after ("new fathers") the birth of their first litter. new fathers approached pu ... | 2009 | 19433091 |
| paternal behavior and testosterone plasma levels in the volcano mouse neotomodon alstoni (rodentia: muridae). | paternal behavior and testosterone plasma levels in the volcano mouse neotomodon alstoni (rodentia: muridae). although initially it was thought that testosterone inhibited the display of paternal behavior in males of rodents, it has been shown that in some species high testosterone levels are needed for exhibition of paternal care. in captivity, males of volcano mouse (neotomodon alstoni) provide pups the same care provided by the mother, with the exception of suckling. here we measured plasmati ... | 2009 | 19637720 |
| testosterone response to courtship predicts future paternal behavior in the california mouse, peromyscus californicus. | in the monogamous and biparental california mouse (peromyscus californicus), paternal care is critical for maximal offspring survival. animals form pair bonds and do not engage in extrapair matings, and thus female evaluation of paternal quality during courtship is likely to be advantageous. we hypothesized that male endocrine or behavioral response to courtship interactions would be predictive of future paternal behavior. to test this hypothesis, we formed 20 pairs of california mice, and evalu ... | 2010 | 19833131 |
| activation of extracellular signal-regulated kinases in social behavior circuits during resident-intruder aggression tests. | using a variety of experimental methods, a network of brain areas regulating aggressive behaviors has been identified in several groups of vertebrates. however, aggressive behavior expressed in different contexts is associated with different patterns of activity across hypothalamic and limbic brain regions. previous studies in rodents demonstrated that short day photoperiods reliably increase both male and female aggression versus long day photoperiods. here we used immunohistochemistry and west ... | 2010 | 19874872 |
| paternal behavior increases testosterone levels in offspring of the california mouse. | paternal care during early development influences pup survivorship in the monogamous and biparental california mouse, peromyscus californicus. moreover, paternal pup retrievals impact development of adult offspring aggression and the neuropeptide vasopressin, yet little is known about the underlying mechanisms of these developmental changes. because testosterone can increase arginine vasopressin and aggression, we hypothesized that paternal pup retrievals increase testosterone levels in prepuber ... | 2010 | 20362577 |
| differences in ultrasonic vocalizations between wild and laboratory california mice (peromyscus californicus). | ultrasonic vocalizations (usvs) emitted by muroid rodents, including laboratory mice and rats, are used as phenotypic markers in behavioral assays and biomedical research. interpretation of these usvs depends on understanding the significance of usv production by rodents in the wild. however, there has never been a study of muroid rodent ultrasound function in the wild and comparisons of usvs produced by wild and laboratory rodents are lacking to date. here, we report the first comparison of wil ... | 2010 | 20368980 |
| estrous phase alters social behavior in a polygynous but not a monogamous peromyscus species. | the social organization of rodent species determines behavioral patterns for both affiliative and agonistic encounters. the neuropeptide oxytocin has been implicated in the mediation of social behavior; however, variability in both neuropeptide expression and social behavior within a single species indicates an additional mediating factor. the purpose of the present comparative study was to investigate social behaviors in naïve mixed-sex pairs of monogamous peromyscus californicus and polygynous ... | 2010 | 20382149 |
| sex differences in hormonal responses to social conflict in the monogamous california mouse. | monogamous species are usually considered to be less likely to exhibit sex differences in behavior or brain structure. most previous studies examining sex differences in stress hormone responses have used relatively sexually dimorphic species such as rats. we examined the stress hormone responses of monogamous california mice (peromyscus californicus) to resident-intruder tests. we also tested males and females under different photoperiods, because photoperiod has been shown to affect both aggre ... | 2010 | 20430027 |
| brief pup exposure induces fos expression in the lateral habenula and serotonergic caudal dorsal raphe nucleus of paternally experienced male california mice (peromyscus californicus). | fathers play a substantial role in infant care in a small but significant number of mammalian species, including humans. however, the neural circuitry controlling paternal behavior is much less understood than its female counterpart. in order to characterize brain areas activated by paternal care, male california mice were separated from their female mate and litter for 3 h and then exposed to a pup or a control object (a glass pebble with the approximate size and oblong shape of a newborn pup) ... | 2010 | 20547210 |
| sex differences in social interaction behavior following social defeat stress in the monogamous california mouse (peromyscus californicus). | stressful life experiences are known to be a precipitating factor for many mental disorders. the social defeat model induces behavioral responses in rodents (e.g. reduced social interaction) that are similar to behavioral patterns associated with mood disorders. the model has contributed to the discovery of novel mechanisms regulating behavioral responses to stress, but its utility has been largely limited to males. this is disadvantageous because most mood disorders have a higher incidence in w ... | 2011 | 21364768 |
| paternal experience suppresses adult neurogenesis without altering hippocampal function in peromyscus californicus. | paternal care is rare among mammals, occurring in ˜6% of species. california mice (peromyscus californicus) are unusual; fathers participate extensively in raising their young and display the same components of parental care as mothers, with the exception of nursing. parenting is a complex experience, having stressful and enriching aspects. the hippocampus is sensitive to experience and responds to both stress and environmental enrichment with changes in structure and function. in rats, where fe ... | 2011 | 21456007 |
| species differences in the winner effect disappear in response to post-victory testosterone manipulations. | evolutionary processes can interact with the mechanisms of steroid hormone action to drive interspecific variation in behavioural output, yet the exact nature of these interactions is poorly understood. to investigate this issue, we compare the endocrine machinery underlying the winner effect (an ability to increase winning behaviour in response to past victories) in two closely related species of peromyscus mice. typically, after winning a fight, california mice (peromyscus californicus) experi ... | 2011 | 21490015 |
| effects of reproductive status on behavioral and endocrine responses to acute stress in a biparental rodent, the california mouse (peromyscus californicus). | in several mammalian species, lactating females show blunted neural, hormonal, and behavioral responses to stressors. it is not known whether new fathers also show stress hyporesponsiveness in species in which males provide infant care. to test this possibility, we determined the effects of male and female reproductive status on stress responsiveness in the biparental, monogamous california mouse (peromyscus californicus). breeding (n=8 females, 8 males), nonbreeding (n=10 females, 10 males) and ... | 2011 | 21557946 |
| independent and additive contributions of postvictory testosterone and social experience to the development of the winner effect. | the processes through which salient social experiences influence future behavior are not well understood. winning fights, for example, can increase the odds of future victory, yet little is known about the internal mechanisms that underlie such winner effects. here, we use the territorial california mouse (peromyscus californicus) to investigate how the effects of postvictory testosterone (t) release and winning experience individually mediate positive changes in future winning ability and antag ... | 2011 | 21771886 |
| paternal experience and stress responses in california mice (peromyscus californicus). | paternal behavior greatly affects the survival, social development, and cognitive development of infants. nevertheless, little research has been done to assess how paternal experience modifies the behavioral characteristics of fathers, including fear and stress responses to a novel environment. we investigated long-term behavioral and physiologic effects of parental experience in mice (peromyscus californicus) and how this response activates the hypothalamic-pituitary-adrenal axis (as measured b ... | 2011 | 21819678 |
| the long-term effects of stress and kappa opioid receptor activation on conditioned place aversion in male and female california mice. | psychosocial stress leads to the activation of kappa opioid receptors (kors), which induce dysphoria and facilitate depression-like behaviors. however, less is known about the long-term effects of stress and kors in females. we examined the long-term effects of social defeat stress on the aversive properties of kor activation in male and female california mice (peromyscus californicus) using a conditioned place aversion paradigm. female california mice naïve to social defeat, formed a place aver ... | 2017 | 28625549 |
| the effects of diet composition on body fat and hepatic steatosis in an animal (peromyscus californicus) model of the metabolic syndrome. | the objective of this research was to determine body composition, total fat content, fat distribution, and serum leptin concentration in hyperlipidemic (high responder, hr) and normolipidemic (low responder, lr) california mice (peromyscus californicus). in our initial experiments, we sought to determine whether differences in regional fat storage were associated with hyperlipidemia in this species. to further characterize the hepatic steatosis in the mice, we performed 2 additional experiments ... | 2011 | 21819679 |
| Corncob Bedding Alters the Effects of Estrogens on Aggressive Behavior and Reduces Estrogen Receptor-a Expression in the Brain. | There is growing appreciation that estrogen signaling pathways can be modulated by naturally occurring environmental compounds such as phytoestrogens and the more recently discovered xenoestrogens. Many researchers studying the effects of estrogens on brain function or behavior in animal models choose to use phytoestrogen-free food for this reason. Corncob bedding is commonly used in animal facilities across the United States and has been shown to inhibit estrogen-dependent reproductive behavior ... | 2011 | 22186416 |
| exposure to extrinsic stressors, social defeat or bisphenol a, eliminates sex differences in dna methyltransferase expression in the amygdala. | chemical and psychological stressors can exert long lasting changes in brain function and behaviour. changes in dna methylation have been shown to be an important mechanism mediating long lasting changes in neural function and behaviour, especially for anxiety-like or stress responses. in the present study, we examined the effects of either a social or chemical stressor on dna methyltransferase (dnmt) gene expression in the amygdala, an important brain region modulating stress responses and anxi ... | 2017 | 28406523 |
| new species of arostrilepis (eucestoda: hymenolepidiae) in members of cricetidae and geomyidae (rodentia) from the western nearctic. | abstract specimens originally identified as arostrilepis horrida from the nearctic are revised, contributing to the recognition of a complex of cryptic species distributed across the holarctic region. previously unrecognized species are described based on specimens in cricetid (neotominae) and geomyid rodents. arostrilepis mariettavogeae n. sp. in peromyscus californicus from monterey county, california, and a. schilleri n. sp. in thomomys bulbivorus from corvallis, oregon are characterized. c ... | 2011 | 22097959 |
| effects of repeated pup exposure on behavioral, neural, and adrenocortical responses to pups in male california mice (peromyscus californicus). | in biparental mammals, the factors facilitating the onset of male parental behavior are not well understood. while hormonal changes in fathers may play a role, prior experience with pups has also been implicated. we evaluated effects of prior exposure to pups on paternal responsiveness in the biparental california mouse (peromyscus californicus). we analyzed behavioral, neural, and corticosterone responses to pups in adult virgin males that were interacting with a pup for the first time, adult v ... | 2017 | 28232065 |
| fatherhood alters behavioural and neural responsiveness in a spatial task. | the hormones and experiences of pregnancy, parturition and lactation have been shown to dramatically remodel the female rat's hippocampus, potentially enhancing behaviours critical for meeting the increased demands of motherhood. previous work in our laboratory has also suggested that pup exposure, apart from pregnancy and lactation, constitutes an important influence on ancillary maternal behaviour (e.g. foraging behaviour). in the present study, we press the parental model further by examining ... | 2011 | 21933288 |
| characterization of vocalizations emitted in isolation by california mouse (peromyscus californicus) pups throughout the postnatal period. | rodent species, such as monogamous and biparental california mice, produce vocalizations as a means of communication. a temporal examination of vocalizations produced by california mice pups in isolation was performed. pup recordings were performed for 3 min at ∼10.00 and 14.00 hrs on early postnatal days (pnd) 2-4, 7, 21, and 28. once initial recordings were finished, pups were returned to the home cage with parents and any siblings for 5 minutes to determine if active biparental responses resu ... | 2017 | 28182483 |
| Using a comparative species approach to investigate the neurobiology of paternal responses. | A goal of behavioral neuroscience is to identify underlying neurobiological factors that regulate specific behaviors. Using animal models to accomplish this goal, many methodological strategies require invasive techniques to manipulate the intensity of the behavior of interest (e.g., lesion methods, pharmacological manipulations, microdialysis techniques, genetically-engineered animal models). The utilization of a comparative species approach allows researchers to take advantage of naturally oc ... | 2011 | 21968462 |
| effects of exposure to bisphenol a and ethinyl estradiol on the gut microbiota of parents and their offspring in a rodent model. | gut dysbiosis may result in various diseases, such as metabolic and neurobehavioral disorders. exposure to endocrine disrupting chemicals (edcs), including bisphenol a (bpa) and ethinyl estradiol (ee), especially during development, may also increase the risk for such disorders. an unexplored possibility is that edc-exposure might alter the gut microbial composition. gut flora and their products may thus be mediating factors for the disease-causing effects of these chemicals. to examine the effe ... | 2016 | 27624382 |
| compatibility drives female preference and reproductive success in the monogamous california mouse (peromyscus californicus) more strongly than male testosterone measures. | female assessment of male attractiveness and how preferred qualities impact reproductive success is central to the study of mate choice. male attractiveness may depend on traits beneficial to the reproductive success (rs) of any female, termed 'universal quality', and/or on behavioral and biological interactions between potential mates that reflect 'compatibility'. the steroid hormone testosterone (t) often underlies male attractiveness in rodents and is associated with enhanced paternal care in ... | 2011 | 22101260 |
| inhibition of vasopressin v1a receptors in the medioventral bed nucleus of the stria terminalis has sex- and context-specific anxiogenic effects. | vasopressin v1a receptors (v1ar) are thought to contribute to the pathophysiology of psychiatric disorders such as anxiety and depression, sparking interest in v1ar as a therapeutic target. although the global effects of v1ar have been documented, less is known about the specific neural circuits mediating these effects. moreover, few studies have examined context-specific v1ar function in both males and females. by using the california mouse, we first studied the effects of sex and social defeat ... | 2016 | 27452721 |
| acute effects of corticosterone injection on paternal behavior in california mouse (peromyscus californicus) fathers. | glucocorticoids are thought to mediate the disruption of parental behavior in response to acute and chronic stress. previous research supports their role in chronic stress; however, no study has experimentally tested the effects of acute glucocorticoid elevation on paternal behavior. we tested the prediction that acute corticosterone (cort) increases would decrease paternal behavior in california mouse fathers and would lead to longer-term effects on reproductive success, as even short-term incr ... | 2011 | 21939660 |
| modeling paternal attentiveness: distressed pups evoke differential neurobiological and behavioral responses in paternal and nonpaternal mice. | with the exception of parturition and lactation, male california deer mice (peromyscus californicus) exhibit the same parental responses toward offspring as conspecific females. a closely related species, peromyscus maniculatus, however, rarely exhibits paternal responses. in the current study, a comparative species approach was used to assess paternal responses in both peromyscus species with varying levels of paternal experience (biological fathers, pup-exposed virgins, and pup-naïve virgins). ... | 2012 | 23262236 |
| minimal metabolism, summit metabolism and plasma thyroxine in rodents from different environments. | rodents were live-trapped in three environments (desert, intermediate and coastal) in southern california, usa, chosen because of the taxonomic overlap of species. upon capture, blood samples were taken and plasma thyroxine concentrations were measured. four species (dipodomys merriami, perognathus fallax, peromyscus eremicus and peromyscus californicus) were returned to the laboratory for measurement of minimal and summit rates of metabolism. heteromyid rodents had significantly lower plasma th ... | 2010 | 2863060 |
| variable infection dynamics in four peromyscus species following experimental inoculation with baylisascaris procyonis. | wild rodents such as peromyscus spp. are intermediate hosts for the zoonotic ascarid baylisascaris procyonis (raccoon roundworm), and previous studies indicate peromyscus leucopus (white-footed mouse) likely serves an important role in parasite ecology. natural infections have been sporadically identified in a few peromyscus spp., but no data are available on differences in susceptibility among the many other species. we compared survival and infection dynamics of b. procyonis in 4 species ( p. ... | 2016 | 27351237 |
| epizootiology of tacaribe serocomplex viruses (arenaviridae) associated with neotomine rodents (cricetidae, neotominae) in southern california. | the objective of this study was to advance our knowledge of the epizootiology of bear canyon virus and other tacaribe serocomplex viruses (arenaviridae) associated with wild rodents in california. antibody (immunoglobulin g [igg]) to a tacaribe serocomplex virus was found in 145 (3.6%) of 3977 neotomine rodents (cricetidae: neotominae) captured in six counties in southern california. the majority (122 or 84.1%) of the 145 antibody-positive rodents were big-eared woodrats (neotoma macrotis) or ca ... | 2015 | 25700047 |
| the pox in the north american backyard: volepox virus pathogenesis in california mice (peromyscus californicus). | volepox virus (vpxv) was first isolated in 1985 from a hind foot scab of an otherwise healthy california vole (microtus californicus). subsequent surveys in san mateo county, ca, revealed serological evidence suggesting that vpxv is endemic to this area, and a second viral isolate from a pinyon mouse (peromyscus truei) was collected in 1988. since then, few studies have been conducted regarding the ecology, pathology, and pathogenicity of vpxv, and its prevalence and role as a potential zoonotic ... | 2012 | 22952799 |
| trichuris peromysci n. sp. from peromyscus californicus, and further notes on t. perognathi chandler, 1945. | | 1946 | 21027513 |
| c-fos changes following an aggressive encounter in female california mice: a synthesis of behavior, hormone changes and neural activity. | although there has been growing interest in the neuroanatomical and physiological mechanisms underlying aggressive behavior, little work has focused on possible mechanisms controlling natural plasticity in aggression. in the current study, we used naturally occurring changes in aggression level displayed by female peromyscus californicus across the estrous cycle and parallel changes in c-fos expression to examine possible brain regions involved in mediating this plasticity. we found that c-fos e ... | 2004 | 15283961 |
| winning territorial disputes selectively enhances androgen sensitivity in neural pathways related to motivation and social aggression. | winning aggressive disputes can enhance future fighting ability and the desire to seek out additional contests. in some instances, these effects are long lasting and vary in response to the physical location of a fight. thus, in principle, winning aggressive encounters may cause long-term and context-dependent changes to brain areas that control the output of antagonistic behavior or the motivation to fight (or both). we examined this issue in the territorial california mouse (peromyscus califor ... | 2010 | 20616093 |
| photoperiod interacts with food restriction in performance in the barnes maze in female california mice. | food restriction has been reported to have positive effects on cognition. this study examines how another environmental factor, daylength, can alter the impact of food restriction on the brain and behavior. female california mice (peromyscus californicus), housed on either long days (16 h of light and 8 h of darkness) or short days (8 h of light and 16 h of darkness), were restricted to 80% of their normal baseline food intake or provided with food ad libitum. testing in a barnes maze revealed t ... | 2010 | 21198981 |
| in three brain regions central to maternal behaviour, neither male nor female phodopus dwarf hamsters show changes in oestrogen receptor alpha distribution with mating or parenthood. | oestrogen receptor (er)alpha immunoreactivity in three brain regions relevant to maternal behaviour (medial preoptic area, bed nucleus of the stria terminalis and medial amygdala) was measured in two species of dwarf hamster that both mate during a postpartum oestrous but differ in expression of paternal behaviour. male and female phodopus campbelli and phodopus sungorus were sampled as sexually naive adults, following mating to satiety, and as new parents. in all brain regions, females expresse ... | 2008 | 19094078 |
| growth of human breast cancers in peromyscus. | modeling breast cancer in general and hormone-sensitive breast cancer, in particular in mice, has several limitations. these are related to the inbred nature of laboratory mice, and do not allow adequate appreciation of the contribution of the host's genetic heterogeneity in tumor growth. in addition, the naturally low estrogen levels of mice makes estradiol supplementation obligatory for tumor growth. here, we show that peromyscus californicus, following cyclosporine-mediated immunosuppression, ... | 2018 | 29343615 |
| effects of a physical and energetic challenge on male california mice (peromyscus californicus): modulation by reproductive condition. | reproduction strongly influences metabolism, morphology and behavior in female mammals. in species in which males provide parental care, reproduction might have similar effects on fathers. we examined effects of an environmental challenge on metabolically important physiological, morphological and behavioral measures, and determined whether these effects differed between reproductive and non-reproductive males in the biparental california mouse (peromyscus californicus). males were paired with a ... | 2018 | 29170256 |
| species differences in urine scent-marking and counter-marking in peromyscus. | species comparisons indicate that scent-marking may differ as a function of mating system and co-housing with the opposite sex ("pairing"). we previously demonstrated that pairing may decrease male solicitation to unfamiliar females in the monogamous peromyscus californicus but not in the non-monogamous p. leucopus. whether urine scent-marking of females changes following pairing and whether scent-marking of paired males varies in response to scent-marks of their cagemate versus those of an unfa ... | 2018 | 29100968 |
| estrogen-dependent modifications to hippocampal plasticity in paternal california mice (peromyscus californicus). | in many biparental species, mothers and fathers experience similar modifications to circulating hormones. with these modifications come alterations in neural structure and function suggesting that neuroendocrine mechanisms may underlie postpartum plasticity in both males and females. in the biparental california mouse (peromyscus californicus), adult neurogenesis is maintained and anxiety-like behavior is attenuated in fathers during the mid-postpartum period. given a causal relationship between ... | 2017 | 28954216 |
| metabolic and affective consequences of fatherhood in male california mice. | physiological and affective condition can be modulated by the social environment and parental state in mammals. however, in species in which males assist with rearing offspring, the metabolic and affective effects of pair bonding and fatherhood on males have rarely been explored. in this study we tested the hypothesis that fathers, like mothers, experience energetic costs as well as behavioral and affective changes (e.g., depression, anxiety) associated with parenthood. we tested this hypothesis ... | 2017 | 28414073 |
| separation increases passive stress-coping behaviors during forced swim and alters hippocampal dendritic morphology in california mice. | individuals within monogamous species form bonds that may buffer against the negative effects of stress on physiology and behavior. in some species, involuntary termination of the mother-offspring bond results in increased symptoms of negative affect in the mother, suggesting that the parent-offspring bond may be equally as important as the pair bond. to our knowledge, the extent to which affect in paternal rodents is altered by involuntary termination of the father-offspring bond is currently u ... | 2017 | 28406977 |
| increased vasopressin expression in the bnst accompanies paternally induced territoriality in male and female california mouse offspring. | while developmental consequences of parental investment on species-typical social behaviors has been extensively characterized in same-sex parent-offspring interactions, the impact of opposite-sex relationships is less clear. in the bi-parental california mouse (peromyscus californicus), paternal retrieval behavior induces territorial aggression and the expression of arginine vasopressin (avp) in adult male offspring. although similar patterns of territorially emerge among females, the sexually ... | 2017 | 28359742 |
| hypothalamic transcriptomic alterations in male and female california mice (peromyscus californicus) developmentally exposed to bisphenol a or ethinyl estradiol. | bisphenol a (bpa) is an endocrine-disrupting chemical (edc) prevalent in many household items. rodent models and human epidemiological studies have linked this chemical to neurobehavior impairments. in california mice, developmental exposure to bpa results in sociosexual disorders at adulthood, including communication and biparental care deficits, behaviors that are primarily regulated by the hypothalamus. thus, we sought to examine the transcriptomic profile in this brain region of juvenile mal ... | 2017 | 28196854 |
| father absence in the monogamous california mouse impairs social behavior and modifies dopamine and glutamate synapses in the medial prefrontal cortex. | the role of the father in psycho-affective development is indispensable. yet, the neurobehavioral effects of paternal deprivation (pd) are poorly understood. here, we examined the behavioral consequences of pd in the california mouse, a species displaying monogamous bonding and biparental care, and assessed its impact on dopamine (da), serotonin (5-ht), and glutamate (glu) transmission in the medial prefrontal cortex (mpfc). in adult males, deficits in social interaction were observed, when a fa ... | 2015 | 24304503 |
| what can animal research tell us about the link between androgens and social competition in humans? | a contribution to a special issue on hormones and human competition. the relationship between androgenic hormones, like testosterone (t), and aggression is extensively studied in human populations. yet, while this work has illuminated a variety of principals regarding the behavioral and phenotypic effects of t, it is also hindered by inherent limitations of performing research on people. in these instances, animal research can be used to gain further insight into the complex mechanisms by which ... | 2017 | 27914879 |