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cohabitation alters vasopressin innervation and paternal behavior in prairie voles (microtus ochrogaster).the density of vasopressin-immunoreactive (avp-ir) fibers in the lateral septum and lateral habenular nucleus is lower in prairie vole fathers--which display paternal behavior under natural conditions-than in sexually naive males. to see if these changes occur before or after the birth of pups, and whether they are related to changes in paternal behavior, we tested paternal responsiveness and measured avp-ir fiber density in the lateral septum, lateral habenular nucleus, medial preoptic area, an ...19947800744
limbic system fos expression associated with paternal behavior.axon-sparing lesions of the medial nucleus of the amygdala (mea) decrease male parental behavior in the highly social prairie vole. to assess further the role of the amygdala in paternal behavior, male and female prairie voles were exposed to a pup or a non-social olfactory stimulus for 3 hours, and cells expressing fos peptide were labelled using immunocytochemistry. compared to controls, males exposed to a pup showed an increase in fos expression in the mea, as well as in several areas with co ...19947834331
sexual maturation in male prairie voles: effects of the social environment.the effects of various social contexts on sexual maturation in captive male prairie voles were investigated. sexual maturity was assessed as the ability of a young male to produce urine capable of activating a diestrous adult female into estrus, as females remain anestrus until they ingest a male urinary chemosignal. in five experiments the postweaning social environments of developing males were manipulated (e.g., presence or absence of dam, sire, or junior litter, exposure to unfamiliar adult ...19947938241
day length influences proceptive behavior of female prairie voles (microtus ochrogaster).prairie voles typically do not breed during the winter; instead, they typically confine breeding to the spring and summer. one proximate cue contributing to this seasonal change in breeding among males is photoperiod. however, photoperiod does not appear to affect female fecundity. female prairie voles are induced into estrus by chemosensory cues in the urine of male conspecifies. females are exposed to these cues when they groom the ano-genital region of males. females that do not groom the ano ...19948047587
place learning by three vole species (microtus ochrogaster, m. montanus, and m. pennsylvanicus) in the morris swim task.place learning was assessed in three species of voles (microtus ochrogaster, m. montanus, and m. pennsylvanicus) with the morris swim task. the performance of all 3 species and both sexes improved with training on the hidden-platform version of the morris swim task, which indicates that all groups were able to learn to locate a spatial goal without local cues. contrary to expectations, no evidence for a sex difference in spatial ability emerged in any of the species. these findings do not provid ...19948026170
oxytocin administered centrally facilitates formation of a partner preference in female prairie voles (microtus ochrogaster).prairie voles (microtus ochrogaster) are monogamous mammals that form male-female pair bonds. partner preference formation, one component of the pair bond in prairie voles, occurs following male-female cohabitation and is facilitated by mating. the peptide hormone oxytocin is released during physical contact and particularly following vaginal stimulation. oxytocin has been implicated in mother-infant bond formation. the present study tested the hypothesis that oxytocin participates in the partne ...19947920590
axon-sparing lesions of the medial nucleus of the amygdala decrease affiliative behaviors in the prairie vole (microtus ochrogaster): behavioral and anatomical specificity.the neural basis of affiliative behavior was examined in the prairie vole, a rodent that exhibits high levels of social contact and paternal behavior. in the first study, the axon-sparing excitotoxin n-methyl-d,l-aspartic acid (nma) produced lesions in the basolateral nucleus of the amygdala or the corticomedial amygdala. males with corticomedial lesions showed significantly less contact with a familiar adult female and a pup when compared with males with lesions of the basolateral nucleus or co ...19947917044
olfactory bulbectomy decreases social behavior in male prairie voles (m. ochrogaster).prairie voles (microtus ochrogaster) are social rodents that show characteristics of monogamy including high levels of social behavior and male parental care. behavioral studies of prairie voles have implicated chemosignals in the control of various components of social behavior and reproduction. in the present study, the role of the olfactory system in male behavior was examined following surgical removal of the olfactory bulbs. decreases in measures of sexual, paternal, and other social behavi ...19948022909
removal of the vomeronasal organ reduces reproductive performance and aggression in male prairie voles.several short-duration tests have demonstrated that the surgical removal of the vomeronasal organ (vnx) from sexually-inexperienced male rodents results in a reduction in copulatory behavior, compared to the effects of sham surgery (sham). we extended these studies to adult male prairie voles, microtus ochrogaster, and substantially increased the duration of the tests. during the initial interactions with females, vnx males spent significantly less time with their noses in close proximity to the ...19948055257
estrogen receptor immunoreactivity in specific brain areas of the prairie vole (microtus ochrogaster) is altered by sexual receptivity and genetic sex.the prairie vole is a small rodent with an unusual reproductive strategy. a sexually naive female vole requires male contact to initiate the maturation of her reproductive functions. contact with an unfamiliar adult male vole increases blood estrogen levels, reproductive tissue weights, and brain nuclear estrogen receptor binding levels of female voles. what is not known is: 1) what is the precise distribution of estrogen receptor containing neurons in the prairie vole brain? 2) does male induce ...19947517750
role of septal vasopressin innervation in paternal behavior in prairie voles (microtus ochrogaster).after being paired with females, male prairie voles show major changes in their social behaviors among which is an increase in paternal responsiveness. these changes are accompanied by fluctuations in the density of the [arg8]vasopressin-immunoreactive (avp-ir) fibers in the lateral septum, suggesting that septal avp might be involved in these changes. to explore a possible involvement of septal avp in paternal responsiveness, we tested whether injections of saline, avp, or the v1a receptor anta ...19948278401
estradiol concentration and the regulation of locomotor activity.we predicted that female prairie voles (microtus ochrogaster) would not increase in locomotor activity during "induced" proestrus. we developed and tested two alternative a priori hypotheses to explain this predicted lack of activity. the non-response hypothesis in which voles cannot, physiologically, increase activity in response to estradiol and, the threshold effect hypothesis in which a minimal concentration of estradiol is necessary to achieve estrus, while higher concentrations influence o ...19958577893
photoperiodic effects on steroid negative feedback in female prairie voles (microtus ochrogaster).breeding in prairie voles is mainly restricted to the autumn and winter of most years. the organization of estrus in female prairie voles is unusual because behavioral estrus is induced by chemosensory stimuli from the urine of adult conspecific males. isolated females exhibit undetectable levels of estradiol and never display estrous behavior, yet exposure to male urine causes a cascade of endocrine changes that evoke estrogen secretion from the ovaries and estrous behavior within 24 hr. in the ...19958575664
interaction of male sensory cues and estradiol in the induction of estrus in the prairie vole.in the prairie vole, estrus and ovulation are induced by stimulation from a male, which also increases the female's gonadal weight and serum estradiol level. it is not known whether the induction of receptivity is dependent solely on an endogenous increase in circulating estradiol or an interaction of increased estradiol and male sensory stimulation. using a dose response paradigm, we examined if a dose of estradiol within physiological range was sufficient to induce receptivity. we also examine ...19958559792
modulation of pair bonding in female prairie voles (microtus ochrogaster) by corticosterone.glucocorticoid levels in animals may respond to and influence the development of social attachments. this hypothesis was tested in prairie voles (microtus ochrogaster), monogamous rodents that form long-term heterosexual pair bonds. in socially naive female prairie voles, cohabitation with an unfamiliar male resulted in a dramatic decline in serum corticosterone levels. when corticosterone levels were reduced via adrenalectomy, females developed partner preferences after 1 h of cohabitation, whi ...19957644488
a gender-specific mechanism for pair bonding: oxytocin and partner preference formation in monogamous voles.previous studies have demonstrated that central administration of vasopressin but not oxytocin facilitates pair bonding in the monogamous male prairie vole. this study tested vasopressin and oxytocin in the formation of the female vole's preference for a particular male partner. initial studies showed that in monogamous female prairie voles (but not in nonmonogamous congeners), mating was followed by a partner preference that endured for at least 2 weeks. nonmating prairie vole females developed ...19957576222
role of male proximity in pregnancy maintenance in prairie voles, microtus ochrogaster.three experiments were conducted to determine whether the presence of a male partner during the gestation period facilitates pregnancy maintenance in female prairie voles. in each of the three experiments more females delivered litters when the male was present and separated from them by a wire-mesh barrier than when the male was absent. the effect was present in both nulliparous and parous females. at the ultimate level this suggests a constraint on male mating strategies. at the proximate leve ...19957610130
the effects of photoperiod on olfactory c-fos expression in prairie voles, microtus ochrogaster.reproduction stops among the majority of prairie voles (microtus ochrogaster) during the winter. short day lengths suppress male reproductive function dramatically in the laboratory, but photoperiod exerts only subtle effects on female reproductive function. thus, the regulation of seasonal breeding in this species remains partially unspecified. in contrast to commonly studied rodents, female prairie voles do not undergo spontaneous estrous cycles; rather, they are induced into estrus by exposur ...19957606471
physiological substrates of mammalian monogamy: the prairie vole model.prairie voles (microtus ochrogaster) are described here as a model system in which it is possible to examine, within the context of natural history, the proximate processes regulating the social and reproductive behaviors that characterize a monogamous social system. neuropeptides, including oxytocin and vasopressin, and the adrenal glucocorticoid, corticosterone, have been implicated in the neural regulation of partner preferences, and in the male, vasopressin has been implicated in the inducti ...19957630584
mating in the monogamous male: behavioral consequences.in monogamous mammals, males typically show selective affiliation with a single mate, high levels of paternal care, and aggression towards conspecifics to protect male and offspring. we have previously described how selective aggression and affiliation increase after mating in the male prairie vole, microtus ochrogaster. the current studies further explored the behavioral changes that follow mating in the male of this species. the first set of experiments tested males on several behavioral measu ...19957777594
coccidian parasites (apicomplexa) from snakes in the southcentral and southwestern united states: new host and geographic records.four hundred thirty-five leptotyphlopid, colubrid, elapid, and viperid snakes were collected from various localities in arkansas, new mexico, oklahoma, and texas, and their feces were examined for coccidian parasites. of these, 131 (30%) were passing oocysts or sporocysts of at least 1 coccidian; 88 (67%) of the infected snakes had only 1 species of coccidian when they were examined. aquatic and semiaquatic snakes accounted for 48% of the infections, whereas strictly terrestrial snakes comprised ...19957876980
species differences in the vasopressin-immunoreactive pathways in the bed nucleus of the stria terminalis and medial amygdaloid nucleus in prairie voles (microtus ochrogaster) and meadow voles (microtus pennsylvanicus).vasopressin-immunoreactive (avp-ir) cells in the bed nucleus of the stria terminalis (bst) and medial amygdaloid nucleus (ma) and their avp-ir projections to the lateral septum were studied in monogamous prairie voles (microtus ochrogaster) and promiscuous meadow voles (m. pennsylvanicus). a sexually dimorphic avp-ir pathway was found in both species; males had more avp-ir cells in the bst and ma, as well as denser avp-ir fibers in the lateral septum, than did females. a significant species diff ...19957619320
oxytocin and rodent sociosexual responses: from behavior to gene expression.in most mammals, gonadal steroid hormones are required for the expression of species-typical reproductive behavior. over the past few years it has become evident that neuropeptides, such as oxytocin (ot) and vasopressin (avp), also play a key role in the regulation of both social and sexual behavior. through studies of gonadal steroid/neuropeptide interactions, we have been able to discover species differences in behavioral and physiological responses to ot that may be associated with species-sp ...19957630585
three experiments on mate choice in meadow voles (microtus pennsylvanicus).species differences in selectivity with respect to mate choice have been hypothesized to be related to mating systems. procedures used in 3 previous experiments on monogamous prairie voles (microtus ochrogaster) and polygamous montane voles (m. montanus) were used with polygamous meadow voles (m. pennsylvanicus). the expectation was that meadow voles would show few preferences. female meadow voles preferred mating with familiar versus unfamiliar males but displayed no preference for unmated vers ...19957705059
adrenocorticoid hormones and the development and expression of mammalian monogamy.based on research with prairie voles, we hypothesize that the unusual patterns of reproduction and social behavior associated with mammalian monogamy may arise as a consequence of normal developmental exposure to high levels of glucocorticoids and/or other hormones of the hpa axis. increased hpa activity could functionally inhibit some of the masculinizing processes expected during the perinatal period. we hypothesize that the unique behavioral, physiological, and anatomical changes associated w ...19958597447
oxytocin and the molecular basis of monogamy.previous studies in rats have implicated central oxytocin (ot) pathways in the onset of maternal behavior, female sexual receptivity, and the response of the pups to social separation. however, the rat is not ideal for studying effects of ot on attachment as rats fail to form selective, enduring social bonds. to study male-female pair bonds, our laboratory has focused on a microtine rodent, the prairie vole, which is monogamous and highly affiliative. adult prairie voles form pair bonds after ma ...19958713971
isolation of mycoplasmas from prairie voles (microtus ochrogaster).a new species of mycoplasmas was isolated from the lungs and nasopharyngeal washings of prairie voles (microtus ochrogaster). clinical signs of disease and microscopic lesions were not observed at the time of this isolation. the organism was cultured in sp4 medium; it grew aerobically, anaerobically, and in 5% co2 in 5 to 7 days, and fermented glucose. transmission electron microscopy revealed the organism to lack a cell wall and to have typical mycoplasmal ultrastructural morphology. the comple ...19958746521
cellular immunity is not compromised by high serum corticosterone concentrations in prairie voles.glucocorticoids compromise immune function in glucocorticoid-sensitive species (e.g., mice), but these immunosuppressive effects may be reduced in glucocorticoid-resistant species. prairie voles (microtus ochrogaster) have been characterized as glucocorticoid-resistant to their high circulating levels of corticosterone. because glucocorticoid-sensitive species display suppressed lymphocyte proliferation in response to elevated blood glucocorticoid levels, proliferative values were hypothesized t ...19968997359
perinatal steroid treatments alter alloparental and affiliative behavior in prairie voles.this experiment was designed to examine the hypothesis that perinatal manipulation of gonadal or adrenal steroids can alter the subsequent expression of juvenile parental (alloparenting) and affiliative behavior in prairie voles (microtus ochrogaster). corticosterone (precort), testosterone (pre-tp), or oil injections (preses) were given on prenatal days 12-20 or on postnatal days 1-6 (cort6, tp6, or ses6, respectively). alloparenting was reduced significantly in females in the cort6 group and i ...19969047281
social isolation in animal models of relevance to neuropsychiatric disorders.animal models of social isolation have been suggested to be relevant to several neuropsychiatric disorders; however, social isolation is usually not purely an alteration of social environment, as it often involves such factors as decreased complexity of the environment, loss of tactile stimulation, and increased metabolic demands of temperature maintenance. in this study, female prairie voles (microtus ochrogaster, a highly social rodent) were assigned to four experimental groups: continued hous ...19968896780
the effects of stress on social preferences are sexually dimorphic in prairie voles.prairie voles (microtus ochrogaster) are monogamous rodents that form pair bonds characterized by a preference for a familiar social partner. in male prairie voles, exposure to either the stress of swimming or exogenous injections of corticosterone facilitate the development of a social preference for a female with which the male was paired after injection or swimming. conversely, adrenalectomy inhibits partner preference formation in males and the behavioral effects of adrenalectomy are reverse ...19968876248
effects of estradiol on sexual receptivity, wheel-running behavior, and vaginal estrus in virgin prairie voles.this study examined the effects of estradiol on sexual receptivity and vaginal estrus in experienced and virgin female prairie voles, and running wheel activity in virgin females. because prairie voles undergo induced ovulation, we predicted that exogenous estradiol would not affect activity patterns nor stimulate lordosis in virgins. females were sc injected with estradiol benzoate (ed) and placed with males, and sexual receptivity was monitored. in experienced females 0.5 micrograms of eb resu ...19968873258
gonadal and photoperiodic influences on body mass regulation in adult male and female prairie voles.nontropical animals commonly use the annual change in photoperiod to phase seasonal adjustments that promote survival and reproduction. to cope with the energetic requirements of winter, many rodents alter body mass in anticipation of winter. photoperiodic adjustments are often mediated by the pineal hormone melatonin; melatonin can exert a primary effect on body mass or secondarily affect body mass by changing blood gonadal steroid levels. the present study sought to determine if prairie voles ...19968928899
photoperiod and population density interact to affect reproductive and immune function in male prairie voles.seasonal breeding of rodents is often associated with changes in adrenal function; altered adrenal function could account, in part, for seasonal changes in immune function and, ultimately, influence seasonal fluctuations in survival. animals commonly monitor the annual change in photoperiod to ascertain the time of year and to make appropriate seasonal adjustments in physiology and behavior. several extrinsic factors affect reproductive responsiveness to photoperiod. the interaction between popu ...19968780222
effects of the selective serotonin reuptake inhibitor fluoxetine on social behaviors in male and female prairie voles (microtus ochrogaster).the selective serotonin reuptake inhibitor fluoxetine modifies social behavior in a number of species, including humans. because the neural substrates for social behavior in prairie voles are sexually dimorphic, we tested whether the effects of fluoxetine on these behaviors differ by sex. parental and pair-bonded voles were chronically treated with fluoxetine or saline and subsequently tested for parental responsiveness. fluoxetine-treated animals displayed a longer latency to exhibit parental r ...19979454669
amygdala but not hippocampal lesions impair olfactory memory for mate in prairie voles (microtus ochrogaster).exposure to an unfamiliar male conspecific results in pregnancy interruption (i.e., the bruce effect) in rodents. unlike most laboratory rodents, female prairie voles (microtus ochrogaster) are induced into estrus by chemosensory stimuli contained in the urine of male conspecifics while grooming the anogenital (a-g) region of unfamiliar males. female prairie voles maintain a brief "memory" for the stud male for 8-10 days after mating. subsequent exposure to the same mate within this 8- to 10-day ...19979374810
sexual and social experience is associated with different patterns of behavior and neural activation in male prairie voles.monogamous prairie voles (microtus ochrogaster) show mating-induced aggression towards conspecific strangers. this behavior is both selective and enduring. the present study was designed to investigate the behavioral conditions for the emergence of selective aggression (by varying prior experience with a female and identity of intruders) and the limbic activation in response to an intruder (by mapping regional staining for c-fos) in male prairie voles. in a first experiment, males that mated wit ...19979367264
exposure to male siblings facilitates the response to estradiol in sexually naive female prairie voles.female prairie voles undergo induced estrus, and require both physical contact with males and exposure to male urine to become reproductively active. this study attempted to determine if physical contact with males enhanced female response to estradiol. two groups of sexually naive females were tested. one was reared without any exposure to males after weaning, and the other was reared with sibling males to 60 days of age. sibling males were used because females avoid direct contact with the uri ...19979177571
high-affinity binding of corticosterone to mammalian neuronal membranes: possible role of corticosteroid binding globulin.the signal transduction mechanisms mediating rapid steroid actions are poorly understood. to characterize corticosteroid interaction with neuronal membranes in a species with rapid behavioral responses to corticosterone, we examined [3h]corticosterone binding to membranes prepared from prairie vole brains. at 22 degrees c, the rates of association and dissociation of [3h]corticosterone with well-washed synaptosomal membranes were very rapid. specific binding was characterized by high affinity (k ...19979191981
exploratory behavior correlates with social organization and is responsive to peptide injections in prairie voles. 19979071412
perinatal hormone exposure alters the expression of selective affiliative preferences in prairie voles.in the present study, perinatal administration of corticosterone and testosterone significantly influenced affiliative preferences only in females. despite the very high levels of steroids given, no significant differences were noted among treated and untreated groups of males. prairie voles apparently are uniquely adapted to tolerate high levels of endogenous steroids. however, females of this species may be capable of exploiting variations in corticosterone levels to regulate sexually dimorphi ...19979071399
intraspecific variation and the presence of a father can influence the expression of monogamous and communal traits in prairie voles. 19979071398
the 5' flanking region of the monogamous prairie vole oxytocin receptor gene directs tissue-specific expression in transgenic mice. 19979071386
differential fos expression following microinjection of oxytocin or vasopressin in the prairie vole brain. 19979071383
social modulation of corticosteroid responses in male prairie voles. 19979071380
molecular aspects of monogamy.comparative studies of monogamous and nonmonogamous voles demonstrate species differences in the regional expression of oxytocin (ot) receptors in the brain. these species differences have not been observed with other neurotransmitter receptors (except vasopressin). species differences for ot receptor distribution were also observed in other microtine and murine species selected as monogamous or promiscuous. these chemical neuroanatomic differences appear to be functionally relevant, as treatmen ...19979071359
characterization of adrenal hormone binding sites in the prairie vole. 19979071389
the hypothalamic-pituitary-adrenal axis of prairie voles (microtus ochrogaster): evidence for target tissue glucocorticoid resistance.basal plasma corticosterone levels in prairie voles (microtus ochrogaster) are extremely high, in the absence of any apparent negative consequences of glucocorticoid excess. we tested the hypothesis that prairie voles are a novel rodent model of target tissue resistance to glucocorticoids. prairie voles had a significantly higher adrenal-to-body weight ratio, 5- to 10-fold greater basal plasma corticosterone, and 2- to 3-fold greater basal plasma acth concentrations than montane voles (microtus ...19979126465
fos immunoreactivity after exposure to conspecific or heterospecific urine: where are chemosensory cues sorted?female prairie voles (microtus ochrogaster) typically require an intact vomeronasal system and exposure to a chemical signal found in urine from male prairie voles to induce uterine growth necessary for reproduction. urine from male mice (mus musculus) does not contain an effective cue for activation of female vole reproduction: after 4 days of exposure to stimuli, voles exposed to urine from female or water had still uteri whereas voles exposed to urine from male voles had large uteri. the init ...19979284509
social environment and steroid hormones affect species and sex differences in immune function among voles.testosterone has bipotential effects on male fitness; that is, it both suppresses immune function and maintains characteristics important for reproductive success. presumably, these effects of testosterone may be more pronounced among polygynous species because testosterone concentrations are generally higher among polygynous than monogamous males. the present study examined sex and species differences in cell-mediated immunity among four arvicoline rodents. the role of mating system and sex ste ...19979344689
sexual differentiation in prairie voles: the effects of corticosterone and testosterone.prairie voles (microtus ochrogaster) exhibit low levels of physical sexual dimorphism and have endogenous basal corticosterone levels that are 5-10 times higher than those measured in rats; prairie voles also do not show a postnatal period of adrenal hyporesponsivity. on the basis of studies in rats suggesting that adrenal hyperactivity during the perinatal period could reduce masculinization or feminize sexual behavior, we hypothesized that adrenal hormones might influence sexual differentiatio ...19979383128
stress affects corticosteroid and immunoglobulin concentrations in male house mice (mus musculus) and prairie voles (microtus ochrogaster).glucocorticoids, secreted in response to perceived stress, can suppress immunoglobulin (ig) levels and compromise immune function in mice and rats. prairie voles (microtus ochrogaster) have been reported to exhibit basal corticosterone concentrations that would cause pathological changes in the immune function of most other rodents. the goals of the present study were to verify that serum corticosterone concentrations are high in prairie voles, as compared with house mice (mus musculus), by meas ...19979406441
ontogeny of oxytocin and vasopressin receptor binding in the lateral septum in prairie and montane voles.adult prairie (microtus ochrogaster) and montane voles (m. montanus) differ in the distribution of oxytocin (ot) and vasopressin (avp) receptor binding in the brain. the present study examined the ontogenetic pattern of these receptor bindings in the lateral septum in both species to determine whether adult differences in the receptor binding are derived from a common pattern in development. in both species, ot and avp receptor binding in the lateral septum were detected neonatally, increased du ...19979466721
gene targeting approaches to neuroendocrinology: oxytocin, maternal behavior, and affiliation.transgenic technology affords exciting new opportunities in the field of behavioral neuroendocrinology. we have extended our research into the behavioral function of oxytocin in maternal and social behavior using two transgenic approaches: (i) targeted deletion of the oxytocin gene in mice and (ii) augmented oxytocin receptor expression in the brain. mice genetically deficient in oxytocin can mate, give birth, and display normal maternal behavior; however, milk ejection and certain aspects of so ...19979213136
species differences in vasopressin receptor binding are evident early in development: comparative anatomic studies in prairie and montane voles.monogamous prairie voles (microtus ochrogaster) and promiscuous montane voles (microtus montanus) exhibit remarkable differences in the distribution of vasopressin (avp) receptors in the adult brain. this difference in receptor distribution is associated with species differences in the behaviors, including pair bond formation and paternal care, found selectively in the monogamous vole. to investigate a potential mechanism for this species difference in avp receptors, the present study examined t ...19979034909
developmental changes in forebrain vasopressin receptor binding in prairie voles (microtus ochrogaster) and montane voles (microtus montanus). 19979071385
adaptive immune responses are linked to the mating system of arvicoline rodents.males generally exhibit reduced immune responses and greater susceptibility to disease than females. the suppressive effect of testosterone on immune function is hypothesized to be one reason why males have lower immune responses than females. presumably, this effect of testosterone should be more pronounced among polygynous than monogamous species because circulating testosterone is higher among polygynous than monogamous males. the present study examined the extent to which sex differences in ...199818811424
pathogenicity of mycoplasma volis in mice and rats.a new species of mycoplasma, m. volis, was isolated from the respiratory tract of clinically normal field-trapped prairie voles (microtus ochrogaster) that were to be housed in close proximity to other rodents. to determine the pathogenic potential of the new mycoplasmal isolate, three groups of rodents (sprague dawley rats, balb/c mice, and severe combined immunodeficient [scid] mice) were intranasally inoculated with 2 x 10(8) color-changing units (ccu) of m. volis and were observed for 4 to 6 ...19989517888
the sequence of giardia small subunit rrna shows that voles and muskrats are parasitized by a unique species giardia microti.the small subunit ribosomal rna (eukaryotic 16s rrna) gene from giardia trophozoites, isolated from 8 different prairie voles and 8 different muskrats, was amplified by the polymerase chain reaction. the 16s rdna was sequenced in its entirety for 2 prairie vole and 2 muskrat giardia. in addition, the 5' 500 nucleotides of the 16s rdna from giardia isolates from each of 6 voles and 6 muskrats were amplified and sequenced. the results show that giardia from voles and muskrats are very similar to e ...19989576501
neurobiological perspectives on social phobia: from affiliation to zoology.social phobia (or "social anxiety disorder") is a prevalent condition that has been the subject of increased scrutiny in recent years. the purpose of this paper is to review the neurobiology of social phobia. it is apparent from the extant literature that this disorder is poorly understood from a neurobiological perspective. there are nonetheless a number of clinical and preclinical observations which, at times, converge to illuminate areas worthy of further study. included in this category are ...19989861470
cytosolic isocitrate dehydrogenase in humans, mice, and voles and phylogenetic analysis of the enzyme family.in this study, we report cdna sequences of the cytosolic nadp-dependent isocitrate dehydrogenase for humans, mice, and two species of voles (microtus mexicanus and microtus ochrogaster). inferred amino acid sequences from these taxa display a high level of amino acid sequence conservation, comparable to that of myosin beta heavy chain, and share known structural features. a caenorhabditis elegans enzyme that was previously identified as a protein similar to isocitrate dehydrogenase is most likel ...19989866202
anatomy and function of extrahypothalamic vasopressin systems in the brain.the most prominent sites of vasopressin (vp) production in the rat brain are the paraventricular nucleus, the supraoptic nucleus, the suprachiasmatic nucleus, the bed nucleus of the stria terminalis (bst), and the medial amygdaloid nucleus (ma). recently a number of new sites have been suggested, including the hippocampus, the diagonal band of broca, and the choroid plexus. this chapter shows how differential regulation of these vp systems can be exploited to identify the contributions of indivi ...199810074777
neuroendocrine perspectives on social attachment and love.the purpose of this paper is to review existing behavioral and neuroendocrine perspectives on social attachment and love. both love and social attachments function to facilitate reproduction, provide a sense of safety, and reduce anxiety or stress. because social attachment is an essential component of love, understanding attachment formation is an important step toward identifying the neurobiological substrates of love. studies of pair bonding in monogamous rodents, such as prairie voles, and m ...19989924738
cooperative breeding and monogamy in prairie voles: influence of the sire and geographical variation.mammalian monogamy is characterized by pair bonding and a relative absence of sexual dimorphism in body size. alloparental behaviour is a characteristic of mammalian cooperative breeding systems. studies of prairie voles, microtus ochrogaster, from stock captured in a resource-abundant habitat in illinois have supported the assumption that this species is a monogamous, cooperative breeder, while other studies of prairie voles from a more arid habitat in kansas have called this assumption into qu ...19989632499
intraspecific variation in the induction of female sexual receptivity in prairie voles.prairie voles (microtus ochrogaster) are monogamous new world rodents which show geographic variation in social behavior. in this study, parameters of female reproduction which might be related to mating system were compared in prairie voles from eastern kansas (kan) versus central illinois (ill). kan females showed a more rapid onset of natural estrus following exposure to a male and were more likely to respond to injections of a low dose (0.5 microg) of exogenous estradiol benzoate than ill fe ...19989662088
voles and vasopressin: a review of molecular, cellular, and behavioral studies of pair bonding and paternal behaviors.several lines of evidence have implicated the neurohypophyseal peptide, vasopressin (vp), in the mediation of complex social behaviors including affiliation, aggression, juvenile recognition and parental behavior. recent studies in microtine rodents using cellular, molecular and behavioral approaches provide additional evidence suggesting a role for vp in the formation of pair bonding and male parental care. monogamous and promiscuous voles differ in social behaviors such as mating-induced pair ...199810074808
oxytocin, vasopressin, and the neuroendocrine basis of pair bond formation.several lines of evidence support a role for oxytocin and vasopressin in complex social behaviors, including parental care, sex behavior, and aggression. recent studies in a monogamous mammal, the prairie vole, suggest an additional role for both peptides in the formation of pair bonds. central administration of oxytocin facilitates and administration of an oxytocin antagonist inhibits partner preference formation in female prairie voles. conversely, vasopressin facilitates and a v1a receptor an ...199810026808
female prairie voles (microtus ochrogaster) fail to form a new pair after loss of mate.we tested experimentally the hypothesis that failure to acquire a new mate by monogamously paired female microtus ochrogaster that lose their mate represents pair-bonding behavior, not a lack of available males. males were removed from reproductive male-female pairs and the females provided an opportunity to pair with unfamiliar sexually inexperienced or experienced males in a semi-natural arena. only three of 22 (13.6%) females formed a new pair, two with inexperienced males and one with an exp ...199824897643
neuroendocrine bases of monogamy.a number of studies have implicated the neurohypophyseal peptides oxytocin and vasopressin in the central mediation of complex social behaviors, including affiliation, parental care and territorial aggression. research on a monogamous rodent, the prairie vole (microtus ochrogaster), suggests that these neuropeptides are also involved in the control of several behaviors associated with monogamy, including pair bonding, paternal care and mate guarding. comparative studies using several species of ...19989498302
prolonged mating in prairie voles (microtus ochrogaster) increases likelihood of ovulation and embryo number.prairie voles are induced ovulators that mate frequently in brief bouts over a period of approximately 24 h. we examined 1) impact of mating duration on ovulation and embryo number, 2) incidence of fertilization, 3) temporal pattern of embryo development, 4) embryo progression through the reproductive tract over time, and 5) embryo development in culture. mating was videotaped to determine first copulation, and the ovaries were examined and the reproductive tracts flushed at 6, 8, 10, 12, 16, 20 ...199910026127
the effects of oxytocin and vasopressin on partner preferences in male and female prairie voles (microtus ochrogaster).this study compared the effects of centrally administered oxytocin (ot) and arginine vasopressin (avp) on partner preference formation and social contact in male and female prairie voles (microtus ochrogaster). after 1 hr of cohabitation and pretreatment with either avp or ot, both males and females exhibited increased social contact and significant preference for the familiar partner. after pretreatment with either an ot receptor antagonist (ota) or an avp (v1a) receptor antagonist (avpa), neit ...199910571489
effects of photoperiod and reproductive responsiveness on pituitary sensitivity to gnrh in male prairie voles (microtus ochrogaster).in order to promote survival and reproductive success, many nontropical rodents inhibit reproduction well in advance of winter in response to decreasing day lengths. male prairie voles (microtus ochrogaster), small temperate zone rodents, vary in their reproductive response to photoperiod. some male voles undergo complete gonadal regression when housed in short days (responders) whereas others fail to inhibit reproduction when exposed to short (i. e., <12 h light/day) day lengths (nonresponders) ...199910562452
developmental exposure to vasopressin increases aggression in adult prairie voles.although the biological roots of aggression have been the source of intense debate, the precise physiological mechanisms responsible for aggression remain poorly understood. in most species, aggression is more common in males than females; thus, gonadal hormones have been a focal point for research in this field. although gonadal hormones have been shown to influence the expression of aggression, in many cases aggression can continue after castration, indicating that testicular steroids are not ...199910535968
prior exposure to oxytocin mimics the effects of social contact and facilitates sexual behaviour in females.the purpose of this study was to determine whether pretreatment with oxytocin could mimic the effects of social contact and enhance sexual receptivity in female prairie voles. female prairie voles require prolonged exposure to males to become sexually active and oxytocin has been shown to play a major role in the establishment of social bonds between males and females. therefore, we hypothesized that prior exposure to exogenous oxytocin, in the absence of males, would enhance sexual activity in ...199910520125
dopamine d2 receptor-mediated regulation of partner preferences in female prairie voles (microtus ochrogaster): a mechanism for pair bonding?this study examined the role of dopamine (da) in partner preference (pp) formation in female prairie voles (microtus ochrogaster). the nonspecific da antagonist haloperidol blocked mating-induced pp, whereas the nonspecific da agonist apomorphine induced pp without mating. the d2 antagonist eticlopride, but not the d1 antagonist sch23390, blocked pp, whereas the d2 agonist quinpirole, but not the d1 agonist skf38393, induced pp without mating. injections of eticlopride before or immediately afte ...199910443786
sex differences in the parental behaviour of adult virgin prairie voles: independence from gonadal hormones and vasopressin.sexually and parentally experienced prairie voles display robust biparental care of pups that is similar between the sexes. little is known, however, about possible sex differences in the parental behaviours of sexually inexperienced prairie voles. parental behaviour of adult virgin male and female prairie voles was examined in sham-operated and gonadectomized subjects treated with vehicle or oestradiol. since arginine-vasopressin (avp) has been suggested to stimulate parental behaviour in sexua ...199910336725
castration does not inhibit aggressive behavior in adult male prairie voles (microtus ochrogaster).the relationship between castration and reduced male aggression is well established. however, anecdotal observations of male prairie voles (microtus ochrogaster) suggest that castration does not reduce aggressive behavior. to investigate the role of testicular androgens on aggressive behavior, castrated or gonadally intact male prairie voles were paired in a neutral arena with a gonadally intact vole. castration did not reduce the frequency of intermale aggression. in experiment 2, aggressive be ...199910222474
effects of isolation on sibling recognition in prairie voles, microtus ochrogaster.traditionally, sibling recognition in prairie voles has been inferred by incest avoidance or lack of reproduction among littermates. previous studies have shown that isolation of sibling prairie voles for 8-15 days causes the breakdown of incest avoidance. however, in a re-evaluation of these studies, using social interactions within sexes (amicable versus agonistic behaviours), rather than incest avoidance, we found that incest avoidance might not be the best criterion for inferring sibling rec ...199910328795
social interactions unmask sex differences in humoral immunity in voles.sex differences in immune function are well established among laboratory rodents, with males typically having lower immunity than females. this sex difference may reflect the suppressive effects of testosterone on immune function. because polygynous males generally have higher circulating testosterone concentrations than monogamous males, sex differences in immune function are hypothesized to be more pronounced among polygynous as compared to monogamous species. sex differences in immune functio ...199910196049
photoperiod affects the gonadotropin-releasing hormone neuronal system of male prairie voles (microtus ochrogaster).in order to maximize survival, animals inhabiting temperate and boreal latitudes exhibit numerous adaptations to changing seasons. central among this suite of coping strategies is the cessation of breeding during the suboptimal conditions of winter. many nontropical rodents inhibit reproduction well in advance of winter in response to short day lengths. male prairie voles (microtus ochrogaster) are small temperate-zone rodents that vary in their reproductive response to photoperiod. some male vo ...199910207275
comparison of the parental behavior of pair-bonded female and male prairie voles (microtus ochrogaster).the behavior of primiparous lactating prairie voles (microtus ochrogaster) and their mates individually interacting with pups was continuously assessed for 45 min after a 2-h parent-litter separation on days 3-4 and 10-11 postpartum. both sexes were highly parental after reunion with the young, and their general pattern of behavior consisted of bouts of quiescence interspersed with bursts of heightened activity. lactating females spent more time than males in contact with pups, and more time bei ...199910222470
forebrain connections of medial agranular cortex in the prairie vole, microtus ochrogaster.fluorescent axonal tracers were used to investigate the connections of medial agranular cortex (frontal area 2, fr2) in male prairie voles. the rostral and caudal portions of fr2 (rfr2 and cfr2) have distinct but partially overlapping patterns of connections. thalamic labeling after cfr2 injections was present in anteromedial nucleus (am), ventrolateral nucleus (vl), lateral segment, mediodorsal nucleus (mdl), centrolateral nucleus (cl), ventromedial nucleus (vm), posterior nucleus (po) and late ...199910382619
pharmacological characterization of central and peripheral type i and type ii adrenal steroid receptors in the prairie vole, a glucocorticoid-resistant rodent.the prairie vole (microtus ochrogaster) has recently been shown to be glucocorticoid resistant; that is, the prairie vole adrenal axis is refractory to dexamethasone challenge, and highly elevated basal corticosterone titers occur without apparent pathophysiology. this study investigates the physiological correlates of glucocorticoid resistance in the prairie vole. we provide a detailed pharmacological characterization of intracellular type i and type ii adrenal steroid receptors in peripheral t ...199910499499
role of steroid hormones in trichinella spiralis infection among voles.males are generally more susceptible to parasite infection than females. this sex difference may reflect the suppressive effects of testosterone and enhancing effects of estradiol on immune function. this study characterized the role of circulating steroid hormones in sex differences after infection with the nematode trichinella spiralis. because testosterone suppresses immune function and because polygynous males have higher circulating testosterone concentrations than monogamous males, sex dif ...199910564208
activation of the immune-endocrine system with lipopolysaccharide reduces affiliative behaviors in voles.in experiment 1, individually housed male meadow voles (microtus pennsylvanicus) and prairie voles (microtus ochrogaster) were injected with lipopolysaccharide (lps) and exhibited the expected decrease in testosterone and increase in corticosterone and interleukin-1beta concentrations 3 hr later, indicating activation of the endocrine and immune systems. in experiment 2, lps- and saline-injected males were tethered in a 3-chamber partner preference apparatus. the time females spent in each chamb ...199910571486
elevated fos-like immunoreactivity in the brains of postpartum female prairie voles, microtus ochrogaster.this study investigated the expression of the protein product of the immediate early gene c-fos in the brains of female prairie voles (microtus ochrogaster) in association with pregnancy and postparturient activities including maternal behavior, lactation and postpartum estrus. fos expression was assessed in female voles that were late in pregnancy, nonpregnant or at one of three different times postpartum (0-8, 12-24, and 24-48 h, respectively). a significant increase in the number of cells dis ...199910639733
increased affiliative response to vasopressin in mice expressing the v1a receptor from a monogamous vole.arginine vasopressin influences male reproductive and social behaviours in several vertebrate taxa through its actions at the v1a receptor in the brain. the neuroanatomical distribution of vasopressin v1a receptors varies greatly between species with different forms of social organization. here we show that centrally administered arginine vasopressin increases affiliative behaviour in the highly social, monogamous prairie vole, but not in the relatively asocial, promiscuous montane vole. molecul ...199910466725
hypothalamic vasopressin gene expression increases in both males and females postpartum in a biparental rodent.in previous studies, the closely related neuropeptide hormones oxytocin and vasopressin have been implicated in the central mediation of parental behaviour. several studies in rats and sheep have demonstrated a role for oxytocin in the initiation of maternal behaviour. recently, a few studies in a biparental species, the prairie vole (microxytocinus ochrogaster) have suggested that vasopressin is important for paternal care. the present study investigated this latter possibility by measuring cha ...200010718906
photoperiod and temperature interact to affect the gnrh neuronal system of male prairie voles (microtus ochrogaster).individuals of numerous species limit energy expenditure during winter by inhibiting reproduction and other nonessential functions. to time these adaptations appropriately with the annual cycle, animals rely on environmental cues that predict, well in advance, the onset of winter. the most commonly studied environmental factor that animals use to time reproduction is photoperiod. rodents housed in short photoperiods in the laboratory or in naturally declining day lengths exhibit pronounced alter ...200010942262
comparative morphology and histochemistry of glands associated with the vomeronasal organ in humans, mouse lemurs, and voles.the vomeronasal organ (vno) is a chemosensory structure of the vertebrate nasal septum that has been recently shown to exist in nearly all adult humans. although its link to reproductive behaviors has been shown in some primates, its functionality in humans is still debated. some authors have suggested that the human vno has the capacity to detect pheromones, while others described it as little more than a glandular pit. however, no studies have utilized histochemical techniques that would revea ...200010967540
babesia microti and borrelia bissettii transmission by ixodes spinipalpis ticks among prairie voles, microtus ochrogaster, in colorado.an endemic transmission cycle of babesia microti was discovered in colorado in the foothills of the rocky mountains. b. microti were found by pcr in 4 of 25 ixodes spinipalpis tick pools tested (a 3.2 % minimum infection rate) and in 87% (13 of 15) of microtus ochrogaster (the prairie vole) spleen and blood samples. using naturally infected i. spinipalpis collected from wild-caught m. ochrogaster as vectors, b. microti and borrelia bissettii were successfully transmitted to laboratory-born m. oc ...200011155930
influence of gonadal hormones on the development of parental behavior in adult virgin prairie voles (microtus ochrogaster).prairie voles (microtus ochrogaster) are a socially monogamous species and both sexes are parental after the birth of pups. in contrast, sexually inexperienced adult prairie voles differ in their behavior towards pups such that virgin males are paternal whereas virgin females are often infanticidal. to test whether there exists a discrete perinatal 'sensitive period' during which gonadal hormones influence this behavior, and to distinguish between the relative contributions of estrogenic and and ...200010996049
3-bromo-7-nitroindazole, a neuronal nitric oxide synthase inhibitor, impairs maternal aggression and citrulline immunoreactivity in prairie voles.lactating female rodents are aggressive against intruders when they are rearing and protecting pups. in prairie voles, microtus ochrogaster, females exhibit a dramatic increase in citrulline immunoreactivity (citrulline-ir) in the paraventricular nucleus (pvn), but not in control regions of the brain, in association with maternal aggression. citrulline is an indirect indicator of nitric oxide (no) synthesis and it is possible that no release in the pvn is an important element in the control of m ...200010869504
temperature and photoperiod interact to affect reproduction and gnrh synthesis in male prairie voles.prairie voles (microtus ochrogaster), like most rodent species, exhibit a phenotypic polymorphism in reproductive response to winter conditions or to short day lengths in the laboratory. laboratory studies on seasonally breeding species have traditionally focused on the role of photoperiod in modulating reproduction and other seasonal adaptions. however, because animals use proximate environmental factors in addition to photoperiod to phase seasonal adaptions with the appropriate time of year, t ...200010844584
dopamine d2 receptors in the nucleus accumbens are important for social attachment in female prairie voles (microtus ochrogaster).the prairie vole (microtus ochrogaster), a monogamous rodent that forms long-lasting pair bonds, has proven useful for the neurobiological study of social attachment. in the laboratory, pair bonds can be assessed by testing for a partner preference, a choice test in which pair-bonded voles regularly prefer their partner to a conspecific stranger. studies reported here investigate the role of dopamine d2-like receptors (i.e., d2, d3, and d4 receptors) in the nucleus accumbens (nacc) for the forma ...200010718272
peripheral pulses of oxytocin increase partner preferences in female, but not male, prairie voles.centrally administered oxytocin (ot) facilitates social behaviors including the partner preferences that characterize the monogamous social system of prairie voles. in contrast peripherally administered ot generally has been ineffective in influencing central processes including behavior. ot from the posterior pituitary gland is released in pulses into the peripheral circulation. we hypothesized that peripherally administered ot, if delivered in repeated injections mimicking these pulses, would ...200010712858
maternal and mating-induced aggression is associated with elevated citrulline immunoreactivity in the paraventricular nucleus in prairie voles.lactating female rodents are fiercely aggressive against intruders when they are rearing and protecting pups. in monogamous prairie voles, microtus ochrogaster, males are parental and exhibit a dramatic increase in aggression, termed mating-induced aggression, in association with reproduction. in mice, the gas, nitric oxide (no), inhibits male aggression, but may have an excitatory role in the production of maternal aggression. in this study, we combined aggressive behavioral testing of female a ...200010701443
in vitro melatonin treatment enhances splenocyte proliferation in prairie voles.the seasonal effects of photoperiod on reproduction are mediated by melatonin, and it is hypothesized that increased immune function in short days is due to the increase in the duration of nightly melatonin secretion. melatonin can act both directly and indirectly on target tissue within the immune system. the present study sought to tease apart the direct and indirect effects of melatonin on one aspect of immune function by examining the influence of in vitro melatonin on splenocyte proliferati ...200010626599
a possible function of the preference for hind nipples in prairie voles (microtus ochrogaster).prairie vole pups (microtus ochrogaster) in laboratory cages prefer hind nipples. in this research, the author observed 8 litters of prairie voles in a seminatural environment to confirm the preference for hind nipples and to determine if young on hind nipples were groomed more frequently or dislodged less frequently than were young on other nipples. prairie vole pups in seminatural environments preferred hind nipples; this preference was illustrated by the progressive use of more anterior nippl ...200111824908
differential expression of vasopressin, oxytocin and corticotrophin-releasing hormone messenger rna in the paraventricular nucleus of the prairie vole brain following stress.forced swimming, as an effective stressor, has been found to facilitate the development of pair bonds in male but to interfere with this behaviour in female prairie voles (microtus ochrogaster). in the present study, we found that forced swimming differentially influenced the expression of messenger rna for vasopressin, oxytocin and corticotrophin-releasing hormone (crh) in the paraventricular nucleus of the hypothalamus (pvn) in the prairie vole brain. forced swimming did not alter vasopressin ...200111722702
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