| phenotypic variation in seasonal adjustments of testis size, body weight, and food intake in deer mice: role of pineal function and ambient temperature. | we investigated pineal function as well as reproductive and energetic characteristics in male deer mice (peromyscus maniculatus) that differentially respond to short photoperiod with full, partial or no gonadal regression. in mice at both high (23 degrees c) and low temperature (1 degree c), these phenotypic differences in reproductive responses to short days were not reflected by differences in urinary excretion of 6-sulphatoxy-melatonin, the main metabolite of pineal melatonin. neither duratio ... | 1997 | 9151428 |
| metabolic fuel availability influences thermoregulation in deer mice (peromyscus maniculatus). | body temperature (tb) was monitored telemetrically in adult deer mice kept in an environmental chamber at low ambient temperature (ta = 15 degrees c). mice were challenged with various doses of 2-deoxy-d-glucose (2dg, a glycolysis inhibitor) or mercaptoacetate (ma, a fatty acid oxidation inhibitor) or a combination of the two drugs. a preliminary study suggested that higher doses of 2dg and ma, either individually or together, tended to produce a transient decrease in tb. in the main experiment, ... | 1997 | 9108570 |
| photoperiod and steroid-dependent adjustments in hypothalamic gonadotropic hormone-releasing hormone, dopamine, and norepinephrine content in male deer mice. | the purpose of this study was twofold: 1) to examine photoperiod-dependent and steroid-dependent adjustments in hypothalamic gnrh and catecholamine content in male deer mice, peromyscus maniculatus, and 2) to evaluate whether the commonly used measure of gnrh accumulation serves as an accurate indicator of altered reproductive function in short-day-housed rodents. deer mice provide a unique animal model in which to evaluate the effect of short day length on the neural substrates directing reprod ... | 1997 | 9047005 |
| glycolytic enzyme binding during entrance to daily torpor in deer mice (peromyscus maniculatus). | associations of glycolytic enzymes with the subcellular particulate fraction of skeletal muscle and heart were examined during entrance to daily torpor in deer mice (peromyscus maniculatus). in skeletal muscle a significant decrease in enzyme binding occurred during torpor entrance for phosphofructokinase, glyceraldehyde-3-phosphate dehydrogenase, and pyruvate kinase, with an additional significant decrease for phosphofructokinase and pyruvate kinase during the deepest state of torpor. reduction ... | 2006 | 9231377 |
| reproductive and immune responses to photoperiod and melatonin are linked in peromyscus subspecies. | the effects of photoperiod and melatonin treatment on reproductive and immune function were assessed in two subspecies of peromyscus maniculatus from different latitudes of origin. in experiment 1, p. m. bairidii (latitude = 42 degrees 51' n) and p. m. luteus (latitude = 30 degrees 37' n) were housed in either long (ld 16:8) or short days (ld 8:16) for 8 weeks. short-day p. m. bairdii displayed reproductive regression and elevated splenocyte proliferation in response to the t-cell mitogen concan ... | 1996 | 8956499 |
| spatial learning in deer mice: sex differences and the effects of endogenous opioids and 60 hz magnetic fields. | we examined the effects of brief exposure to weak 60 hz extremely low frequency (elf) magnetic fields and opioid systems on spatial behavior and learning in reproductive adult male and female deer mice, peromyscus maniculatus. sex differences were evident in spatial performance, with male deer mice displaying significantly better performance than female mice in the morris water maze, whereby animals had to acquire and retain the location of a submerged hidden platform. brief (maximum 5 min) expo ... | 1996 | 8888582 |
| photoperiod and temperature interact to affect immune parameters in adult male deer mice (peromyscus maniculatus). | nontropical rodents often experience large seasonal fluctuations in both food availability and energy demands. the energy required for thermoregulation is highest during the winter when food availability may be at an annual minimum. failure to cope with winter probably accounts, in part, for the increased prevalence of disease and death relative to that in summer. winter conditions may elevate circulating glucocorticosteroid levels, which can compromise immune function. to increase the odds of s ... | 1996 | 8744237 |
| copper, zinc, and cadmium concentrations in peromyscus maniculatus sampled near an abandoned copper mine | concentrations of zinc, copper, and cadmium were determined in soil and liver, kidney, bone and stomach contents of deer mice (peromyscus maniculatus) from two sites near an abandoned mine and one control site, on vancouver island, british columbia, canada. soil concentrations of copper were significantly elevated at the mine and off site vs the reference site. in contrast, there was no difference in soil cadmium and zinc concentrations between the mine and reference site. concentrations of copp ... | 1996 | 8661524 |
| auditory-evoked brainstem responses in the torpid deermouse. | this study examined auditory-evoked brainstem responses (abr) in the deermouse (peromyscus maniculatus) during torpor and arousal. the abr of the euthermic deermouse consisted of five waves occurring in a time frame of 10 ms. during torpor, abr wave i could be elicited at slow, but not fast stimulation rates indicating variability in neural activity along the auditory pathway. arousal was heralded by the appearance of all the components of the abr evoked in response to both slow and fast click r ... | 1996 | 8848480 |
| differential testicular responses to short daylength in deer mice are reflected by regional and morphological differences in the gnrh neuronal system. | male deer mice (peromyscus maniculatus) respond to short photoperiod with a range of spermatogenic responses. about one-third of all short day exposed mice exhibit a complete cessation of spermatogenesis (reproductive responsive), while about an equal number remain reproductively competent (reproductive nonresponsive). these differential spermatogenic responses are mirrored by endocrine measures; reproductive responsive males exhibit reduced circulating levels of testosterone and luteinizing hor ... | 1995 | 7583239 |
| p-nitrosophenol reduction by liver cytosol from adh-positive and -negative deermice (peromyscus maniculatus). | liver cytosolic fractions are known to catalyze the reduction of certain c-nitroso compounds to their corresponding hydroxylamines and amines. alcohol dehydrogenase (adh), nad(p)h:quinone oxidoreductase, and xanthine and aldehyde oxidases have been implicated as c-nitroso reductases. to probe the role of these cytosolic enzymes in the reduction of c-nitroso compounds we have studied the effects of classical inhibitors of these enzymes on the ability of liver cytosolic fractions from adh+ and adh ... | 1995 | 7532387 |
| toxicological foundations of ecological risk assessment: biomarker development and interpretation based on laboratory and wildlife species. | ecological risk assessments based on chemical residue analysis and species demographics tend to ignore the bioavailability and bioaccumulation of the chemicals of concern. this study describes the incorporation of mechanistically based biomarkers into an ecological risk assessment of a poly-cyclic aromatic hydrocarbon (pah)-contaminated site. a combination of soil residue analysis, tissue residue analysis, biomarkers in one-site trapped animals and biomarkers in animals confined to enclosures wa ... | 1994 | 7713037 |
| role of gonadal steroids and inhibitory photoperiod in regulating body weight and food intake in deer mice (peromyscus maniculatus). | we investigated the role of declining daylength and gonadal steroids on body weight and food intake in male deer mice (peromyscus maniculatus). this species was chosen for study because individual males display different reproductive responses to inhibitory daylength. about one-third of all mice exposed to short days undergo testicular regression and exhibit reduced circulating levels of luteinizing hormone and testosterone (reproductive responsive males). in contrast, testicular function and ci ... | 1994 | 8073049 |
| day length affects immune cell numbers in deer mice: interactions with age, sex, and prenatal photoperiod. | the extent to which day length affects immune function was examined in the present study. three goals were pursued: 1) to confirm and extend the observation that the immune systems of adult deer mice (peromyscus maniculatus) are responsive to changes in photoperiod, 2) to examine the development of the photoperiod-associated changes in immune function, and 3) to discover whether photoperiodic information transmitted to the young during gestation influences immune function. in experiment 1, adult ... | 1994 | 8067473 |
| influence of mustelid semiochemicals on population dynamics of the deer mouse (peromyscus maniculatus). | the influence of mustelid anal-gland compounds on population dynamics of the deer mouse (peromyscus maniculatus) was investigated. densities of deer mice were not found to be significantly different between treated and control areas. however, on average, numbers of deer mice were lower on treated areas following the july treatments of 1991 and 1992. survival rates appeared to be lower and more erratic on treated than control areas in 1991; however, there were no statistically significant differe ... | 1994 | 24242120 |
| sexually dimorphic spatial learning varies seasonally in two populations of deer mice. | spatial learning in photoperiodically induced breeding (reproductive) and non-breeding (non-reproductive) adult male and female deer mice (peromyscus maniculatus) was examined in a morris water-maze task. sexually mature, adult male and female deer mice that were derived from either a mainland population (p. m. artemisiae) or an island population (p. m. angustus) were required to learn the spatial position of a hidden, submerged platform in a water maze. deer mice were tested either during the b ... | 1994 | 8173954 |
| sex differences in the antinociceptive effects of the enkephalinase inhibitor, sch 34826. | the effects of endogenous opioid peptides are limited by proteolytic enzymes such as endopeptidase 24.11 ("enkephalinase"), which cleaves the gly-phe bonds in met- and leu-enkephalin. sch 34826 [(s)-n-[n-[1-[(2,2-dimethyl-1,3-dioxolan-4- yl)methoxy]carbonyl]-2-phenylethyl]-l-phenyl-alanine-b-alanine] is a potent, highly specific, enkephalinase inhibitor that has marked analgesic effects in laboratory rodents. the present study compared the effects of sch 34826 on nociception and restraint stress ... | 1993 | 8309954 |
| diurnal rhythms of 5-ht1a and 5-ht2 receptor binding in euthermic and torpor prone deermice, peromyscus maniculatus. | deermice display both spontaneous and induced daily torpor bouts, attaining minimum body temperatures of 15-20 degrees c. there is evidence that brain serotonin may be involved in the initiation and/or maintenance of torpor. inhibition of serotonin [5-hydroxytryptamine (5-ht)] synthesis markedly reduces the duration and depth of torpor. because a certain percentage of deermice will not enter torpor under any circumstances, we were able to compare 5-ht receptor subtypes in deermice that readily e ... | 1993 | 8415817 |
| season affects tolerance of cohabitation by deer mice. | we measured the resting metabolic rates of peromyscus maniculatus for 7 days before and 7 days following forced pairing in order to determine whether seasonal light cycles influenced the rates of behavioral and metabolic habituation of deer mice to cohabitation. we had earlier shown that winter photoperiod and/or huddling results in lower resting metabolic rates and core temperatures of deer mice. seasonal photoperiods were simulated by conditioning wild-caught mice to 24-h light cycles with dif ... | 1993 | 8451332 |
| sex differences in the effects of tyr-mif-1 on morphine- and stress-induced analgesia. | there is evidence suggesting that the endogenous tetrapeptide, tyr-mif-1 (tyr-prol-leu-gly-amide), has antagonistic or modulatory effects on opioid-mediated analgesia. there is also substantial evidence for sex differences in opioid effects, whereby male rodents display greater levels of opioid-mediated analgesia than females. in the present study, determinations were made of the effects of tyr-mif-1 on morphine- and restraint stress-induced opioid analgesia in adult male and female deer mice, p ... | 2013 | 1362981 |
| effect of reproductive function on cold tolerance in deer mice. | thermoregulatory responses were evaluated in male deer mice (peromyscus maniculatus nebrascensis) after exposure to short photoperiod and either warm or cold ambient temperature (t(a)). deer mice were chosen for this study because males exhibit differential reproductive responses to short day length (sd); this difference has a genetic basis, and both phenotypes are found within natural breeding populations. deer mice undergoing sd-induced gonadal regression significantly improved their cold limi ... | 1992 | 1415794 |
| the effects of feeding triiodothyronine on reproductively inhibited prairie deermice (peromyscus maniculatus bairdii) from laboratory populations. | 1. two reproductively inhibited populations were given 250 ng triiodothyronine (t3) per gram of food for 35 days to elevate the reduced serum thyroid hormone concentration previously demonstrated in reproductively inhibited animals and to determine if the treatment would promote recovery. 2. per capita food intake was significantly increased but per cent body fat tended to decrease and body weight did not significantly increase during t3 treatment. 3. mean testis and seminal vesicle weights of t ... | 1992 | 1354582 |
| tissue-specific metabolism during normothermy and daily torpor in deer mice (peromyscus maniculatus). | previous work with deer mice (peromyscus maniculatus) has demonstrated that a significant acidosis occurs during daily torpor. in addition, carbohydrate levels are significantly lower, whereas fatty acid and ketone levels are significantly higher during torpor. the present study examined the effects of these in vivo acid-base and metabolite adjustments on in vitro 14c-glucose metabolism in tissues taken from normothermic and torpid deer mice. glucose oxidation in liver and vastus lateralis taken ... | 1992 | 1569409 |
| photoperiod influences the critical caloric intake necessary to maintain reproduction among male deer mice (peromyscus maniculatus). | the concept of critical day length is well established among rodents; reproductive function is maintained when day lengths are greater than some specific threshold. in addition to day length cues, seasonal breeding in deer mice can also be regulated by food availability. the caloric threshold necessary to support reproduction remains unspecified for seasonally breeding rodents. the present study examined the interaction between photoperiod and food availability on reproductive function in adult ... | 1992 | 1536898 |
| differential reproductive response to short photoperiod in deer mice: role of melatonin. | inhibitory photoperiod differentially effects reproduction in deer mice (peromyscus maniculatus nebrascensis). pituitary-testicular function is arrested in about one-third of short-day exposed males (reproductively responsive mice), while an equal number remain fertile (reproductively nonresponsive mice). both phenotypes are found in natural populations and their disparate reproductive responses have a genetic basis. to assess whether this difference is attributable to a prepineal/pineal or post ... | 1991 | 1779421 |
| estimation of single generation migration distances from geographic variation in animal mitochondrial dna. | a new approach is introduced for the analysis of dispersal from the geographic distributions of mtdna lineages. the method is based on the expected spatial distributions of lineages arising under a multigeneration random walk process. unlike previous methods based on the predicted equilibria between genetic drift and gene flow, this approach is appropriate for non-equilibrium conditions, and yields an estimate of dispersal distance rather than dispersal rate. the theoretical basis for this metho ... | 1991 | 28567865 |
| different spatial scales of adaptation in the climbing behavior of peromyscus maniculatus: geographic variation, natural selection, and gene flow. | patterns of geographic variation in tree-climbing ability of peromyscus maniculatus were used to examine the influence of spatial variation in natural selection and gene flow on the genetic divergence of climbing behavior among populations. offspring of adults of two subspecies sampled from 10 localities in montane conifer forest, conifer woodland, and desert scrub/grassland habitats were raised in the laboratory and tested to determine their tree-climbing ability (the maximum diameter artificia ... | 1990 | 28569032 |
| in vivo formation of a free radical metabolite of ethanol. | free radical metabolism of ethanol has been suggested as a factor in its hepatotoxicity. although evidence of lipid radical formation due to ethanol treatment in vivo has been reported, free radicals from ethanol itself have not been detected in living animals. however, by applying the epr spectroscopy technique of spin trapping to the study of ethanol-treated alcohol dehydrogenase-deficient deermice (peromyscus maniculatus), we have detected the alpha-(4-pyridyl-1-oxide)-n-t-butylnitrone (pobn) ... | 1990 | 2370854 |
| tests of preferences of adult deer mice (peromyscus maniculatus bairdi) for siblings versus nonsiblings. | seven experiments were conducted to test the performance of adult deer mice (peromyscus maniculatus bairdi) in discriminating and preferring siblings versus nonsiblings. in two experiments there was no indication of preferences based on odor alone. further, there was no indication of kin discrimination in a seminatural enclosure. there was some indication that in a test apparatus, estrous females associate preferentially with male siblings rather than nonsiblings. the effect appears dependent on ... | 1990 | 2364663 |
| tests of preferences of young deer mice (peromyscus maniculatus bairdi) for siblings versus nonsiblings. | three experiments were conducted to test the performance of young deer mice (peromyscus maniculatus bairdi) in associating preferentially with siblings versus nonsiblings. in experiment 1, neither males nor females preferred caged siblings versus nonsiblings. in experiment 2, with full contact permitted, nonsibling males were in contact as much as were sibling males. in experiment 3, with pairs of littermate pairs permitted full contact, there was no significant differential association. althoug ... | 1990 | 2364662 |
| developmental changes in opiate-induced analgesia in deer mice: sex and population differences. | we examined developmental changes in nociception and mu (morphine) and kappa (u-50,488) opiate-induced analgesia in male and female deer mice of two different populations; peromyscus maniculatus artemisiae from a mainland region and p. m. angustus from a small island. both populations displayed significant developmental changes in nociception and morphine (10 mg/kg) and u-50,488 (10 mg/kg)-induced analgesia. basal thermal response latencies (nociceptive responses) and the levels of mu and kappa ... | 1990 | 2163727 |
| sex differences in the inhibitory effects of the nmda antagonist, mk-801, on morphine and stress-induced analgesia. | we examined the effects of intraperitoneal administrations of the noncompetitive nmda receptor antagonist, (+) mk-801, its inactive enantiomer, (-) mk-801, and the prototypic opiate antagonist, naloxone, on restraint- and morphine-induced analgesia in male and female deer mice, peromyscus maniculatus. both restraint (30 min) and morphine (1.0 mg/kg) induced significant analgesic responses with male mice displaying significantly greater levels of opioid-induced analgesia than female animals. thes ... | 1990 | 2162721 |
| intracellular ph during daily torpor in peromyscus maniculatus. | intracellular and extracellular acid-base parameters during normothermy and daily torpor were examined in deer mice (peromyscus maniculatus). [14c]dimethyloxazolidinedione and [3h]inulin were used to assess intracellular ph in liver, heart, skeletal muscle, and brain. buffering capacities were determined using tissue homogenates. a significant increase in plasma pco2 and cco2 during daily torpor indicates a respiratory acidosis. all tissues experienced a reduction in the calculated dissociation ... | 1990 | 2335594 |
| hypothalamic monoamines and their metabolites in the deermouse, peromyscus maniculatus, during daily torpor. | deermice, subjected to food rationing, an ambient temperature below thermal neutrality and short photoperiod, were sacrificed in euthermia or during daily torpor. hypothalamic monoamine and metabolite levels were quantified by hplc with electrochemical detection. significant elevations in the levels (pg/microgram protein) of dopamine, 3,4-dihydroxyphenylacetic acid, and homovanillic acid were noted in the torpid animals. the concentrations of norepinephrine and serotonin displayed no significant ... | 1990 | 2297395 |
| muscle capillary tortuosity in high altitude mice depends on sarcomere length. | at given capillary-to-fiber ratio and sarcomere length, capillary tortuosity determines capillary length and the geometry of blood-tissue exchange in muscles. it is therefore an important determinant of the potential efficiency of o2 supply to the muscle fibers. reports have indicated that capillary tortuosity increases with adaptation to hypoxia. unfortunately, sarcomere length was not taken into account. because capillary tortuosity increases substantially as the muscle shortens, it is importa ... | 1989 | 2749029 |
| a reevaluation of chromosomal variation in populations of peromyscus maniculatus along an elevational gradient. | | 1989 | 28568496 |
| hemoglobin polymorphisms in deer mice (peromyscus maniculatus): physiology of beta-globin variants and alpha-globin recombinants. | wild populations of deer mice (peromyscus maniculatus) contain hemoglobin polymorphisms at both alpha-globin (hba, hbc) and beta-globin (hbd) loci. population gene frequencies of beta-globin variants (d0 and d1 haplotypes) are not correlated with altitude, whereas a1 c1 alpha-globin haplotypes are fixed in low-altitude populations, and a0 c0 haplotypes reach near fixation at high altitudes. we examined the effects of alpha- and beta-globin variants on blood oxygen affinity and on aerobic perform ... | 1988 | 28563877 |
| alpha-chain hemoglobin polymorphisms are correlated with altitude in the deer mouse, peromyscus maniculatus. | in deer mouse (peromyscus maniculatus) populations in the western united states, alpha-globin haplotype frequency, beta-globin haplotype frequency, and base-line blood oxygen affinity (measured after acclimation to low altitude) show strong correlations with native altitude. the correlations improve when an average regional altitude is substituted for the local altitude at collection sites. this substitution roughly compensates for the effects of gene exchange between populations in areas of hig ... | 1988 | 28563873 |
| kinship, familiarity, aggression, and dominance in deer mice (peromyscus maniculatus) in seminatural enclosures. | this study was designed to test the effects of kinship and postweaning familiarity on male-male aggressive interactions in deer mice (peromyscus maniculatus) in a more naturalistic situation than that of most tests of kin discrimination. familiar males (i.e., those housed together from weaning) displayed significantly less aggression than unfamiliar males; kinship per se did not appear to affect levels of aggression. in addition, dominant males copulated more than subordinates and under some con ... | 1988 | 3165063 |
| chromosomal pairing in deer mice heterozygous for the presence of heterochromatic short arms. | the pattern of chromosomal pairing was analyzed in male deer mice (peromyscus maniculatus and peromyscus sitkensis) heterozygous for the presence of heterochromatic short arms. g- and c-banding of somatic metaphases indicated that the presence of heterochromatic short arms increased the length of chromosome 4 by 15% in p. sitkensis and that of chromosome 8 by 9% in p. maniculatus. analysis of silver-stained late zygotene and early pachytene nuclei revealed a low frequency of unequal axial length ... | 1988 | 3371655 |
| novelty-induced opioid analgesia in deer mice (peromyscus maniculatus): sex and population differences. | exposure to a new environment elicited significant, naloxone (1.0 mg/kg) reversible analgesic responses in three different populations of deer mice; peromyscus maniculatus artemisiae from the mainland, and p. m. angustus and p. m. triangularis from small marine islands. in all cases male deer mice displayed significantly greater levels of analgesia than females. in addition, the levels of analgesia were significantly greater in the insular than in the mainland populations. these results indicate ... | 1988 | 3345191 |
| the relationship between food intake, body fat and reproductive inhibition in prairie deermice (peromyscus maniculatus bardii). | 1. reproductively-inhibited deermice selected from four laboratory populations consumed significantly less food than reproductively-proven pairs. 2. reproductively-inhibited animals predominantly, but not consistently, had reduced total body fat compared with reproductively capable deermice. 3. the per capita food consumption rate of two populations followed for 26 weeks since founding, decreased over time to about 65% of the daily intake of the proven animals used to found the populations. 4. a ... | 1988 | 2899486 |
| cytochrome oxidase activity in brown fat varies with reproductive response and use of torpor in deer mice. | reproductive responses and thermogenic properties of brown adipose tissue (bat) were evaluated in individuals from an outbred population of deer mice (peromyscus maniculatus nebrascensis) after 10 weeks exposure to short photoperiod (8:16 light:dark) and cold ambient temperature (2 degrees c). deer mice populations are composed of phenotypes that differ in their reproductive response to environmental cues. these phenotypes also differ in body temperature regulation as indicated by their use of d ... | 1988 | 2845453 |
| stress-induced opioid analgesia and activity in deer mice: sex and population differences. | we compared restraint stress-induced opioid, analgesic and locomotory responses of 4 different populations of male and female deer mice, peromyscus maniculatus artemisiae and p. m. nebrascensis from mainlands, and p. m. angustus and p. m. triangularis from small islands. all of the deer mice displayed immobilization-induced analgesia which was blocked by the prototypical mu-opiate antagonist, naloxone (1.0 mg/kg). in all of the populations males displayed significantly greater levels of analgesi ... | 1987 | 3427425 |
| analysis of mitochondrial dna polymorphisms among channel island deer mice. | mitochondrial dna (mtdna) from 131 deer mice, peromyscus maniculatus, collected on the eight california channel islands and from seven southern california mainland locations, was isolated and analyzed for restriction endonuclease fragment polymorphisms. a total of 26 mtdna genotypes were distinguishable among the deer mice sampled. all of the island samples had mtdna restriction-fragment patterns not found among the mainland samples. distributions of specific restriction-fragment patterns provid ... | 1987 | 28564361 |
| sex and day-night differences in opiate-induced responses of insular wild deer mice, peromyscus maniculatus triangularis. | we examined the effects of mu and kappa opiate agonists on the day- and night-time nociceptive, locomotory and ingestive behaviors of an island population of wild male and female deer mice, peromyscus maniculatus triangularis. the prototypical mu opiate agonist, morphine, had significant analgesic and locomotory effects, which were blocked by naloxone, and the specific delta opiate antagonist, ici 154,129, respectively. the specific kappa opiate agonist, u-50,488, had significant analgesic actio ... | 1987 | 3659070 |
| chromosomal variation in peromyscus maniculatus populations along an elevational gradient. | | 1987 | 28563794 |
| gonadal regression induced by caloric restriction is not mediated by the pineal gland in deer mice (peromyscus maniculatus). | the role of the pineal gland in mediating reproductive regression in response to nonphotoperiodic cues was assessed. a proportion of deer mice (peromyscus maniculatus) undergo gonadal regression subsequent to moderate food restriction. the reproductive regression after inanition qualitatively and quantitatively resembles short-day-induced regression. the physiological mechanisms responsible for gonadal regression after food restriction are unknown. the hypothesis that the mechanisms underlying p ... | 1987 | 3625465 |
| effects of three plant growth regulators on the immune response of young and aged deer mice peromyscus maniculatus. | | 1986 | 3729546 |
| a model to assess survival mechanisms of parasites in a genetically defined host system. | we examined a host system (peromyscus maniculatus) in which a single autosomal gene controls susceptibility or resistance to infection by the cestode parasite hymenolepis citelli. parasite deaths of both primary and secondary (challenge) infections were examined, using a probabilistic model, to see if deaths were random and uncorrelated within each genotype. within susceptible hosts, post-patent survival of primary worms was not random and heterogeneity was due to among-host effects rather than ... | 1986 | 3714298 |
| effects of intrahypothalamically administered norepinephrine, serotonin and bombesin on thermoregulation in the deermouse (peromyscus maniculatus). | norepinephrine, serotonin, and bombesin administered intrahypothalamically affected thermoregulation in the deermouse, peromyscus maniculatus. at a ta of 22 degrees c, doses of 3 micrograms and 6 micrograms of ne resulted in transient hypothermia (maximum drop of 1.6 +/- 1.0 degrees c and 4.3 +/- 2.3 degrees c, respectively). a 1.5 microgram dose of 5-ht induced a persistent hyperthermia (maximum increase of 1.8 +/- 0.8 degrees c) which persisted for more than 2 h. a 6 microgram dose of 5-ht did ... | 1986 | 3947967 |
| photic cues induce multiple neuroendocrine adjustments in testicular function. | neuroendocrine responses were evaluated in an outbred population of deer mice (peromyscus maniculatus nebrascensis) after exposure to an inhibitory photoperiod (8:16 light-dark) for 10 wk. deer mice were chosen as an animal model for this study because they are typical of naturally selected species that rely on environmental factors to signal the onset or cessation of annual reproductive effort. short photoperiods induced multiple neuroendocrine adjustments as judged by three types of spermatoge ... | 1986 | 3946637 |
| bioenergetic benefits of huddling by deer mice (peromyscus maniculatus). | both short photoperiod and communal social living conserve metabolic energy by deer mice held in thermal neutral ambient temperatures. initial socialization was energetically more costly than solitary living, but huddling behaviors reduced thermal conductance and mass specific metabolic rate by 30% within 5 days. while short photoperiod reduced metabolic energy expenditure by decreasing thermoregulatory demand, huddling mediated behavioral conservation was achieved with hyperthermic core tempera ... | 1986 | 2879682 |
| hepatotoxicity due to allyl alcohol in deermice depends on alcohol dehydrogenase. | the role of alcohol dehydrogenase in the hepatic necrosis due to allyl alcohol was studied in two strains of the deermouse, peromyscus maniculatus. mice of the alcohol dehydrogenase-negative (adhn) strain which lack alcohol dehydrogenase activity were resistant to allyl alcohol toxicity. in contrast, dose-dependent necrosis of periportal regions of the liver and increases in plasma levels of lactate dehydrogenase, sorbitol dehydrogenase and sgot were observed in plasma from alcohol dehydrogenase ... | 2013 | 2933316 |
| studies of pericopulatory pregnancy blockage and the gestation period in deer mice (peromyscus maniculatus). | it has previously been shown that female deer mice in cycling estrus that copulate with or are exposed to more than one male at the time of mating have a lower probability of delivering a litter than when mating with and being exposed to just one male. in the present research the effect of post-mating exposure to the bedding of a strange versus a familiar male was studied in females in postpartum estrus. in four experiments females in postpartum estrus were protected from pericopulatory pregnanc ... | 1985 | 4007797 |
| reproductive development in male deer mice exposed to aggressive behavior. | male deer mice (peromyscus maniculatus bairdii) were reared in a long photoperiod and housed individually from 3 weeks of age until they were killed 2, 4, or 6 weeks later. males that were exposed to aggressive females for 2 min, three times per week, were of normal body weight and healthy, but had smaller reproductive organs than did males exposed to a control treatment. reproductive development in male deer mice is responsive to at least two classes of social stimuli: pheromones and aggressive ... | 1985 | 4039275 |
| low p50 in deer mice native to high altitude. | whereas it is widely believed that animals native to high altitude show lower o2 partial pressures at 50% hemoglobin saturation (p50) than do related animals native to low altitude, that "fact" has not been well documented. consequently, p50 at ph 7.4, pco2(7.4), the co2 bohr effect, and the buffer slope (delta log pco2/delta ph) were determined via the mixing technique in peromyscus maniculatus native to a range of altitudes but acclimated to 340 or 3,800 m. pco2(7.4) and buffer slope were subs ... | 1985 | 3917990 |
| effects of ambient temperature and altitude on ventilation and gas exchange in deer mice (peromyscus maniculatus). | the effects of different ambient temperatures (ta) on gas exchange and ventilation in deer mice (peromyscus maniculatus) were determined after acclimation to low and high altitude (340 and 3,800 m). at both low and high altitude, oxygen consumption (vo2) decreased with increasing ta at ta from -10 to 30 degrees c. the vo2 was 15-20% smaller at high altitude than at low altitude at ta below 30 degrees c. increased vo2 at ta below thermoneutrality was supported by increased minute volume (vi) at b ... | 1985 | 3837039 |
| metabolic and thermoregulatory effects of photoperiod and melatonin on peromyscus maniculatus acclimatization. | a photoperiod-related seasonal rhythm in active period (scotophase), metabolic rate and core temperature was documented for animals held at 21.0 +/- 0.1 degrees c ambient; animals that were habituated to long nights (10:14ld) had a greater metabolic reserve than those held in summer photoperiods (14:10ld). while relative weights of gonads and sex accessory tissues of mice show typical "winter" regression, interscapular brown adipose tissue mass was unaffected by photoperiod; moreover, ibat beta ... | 1985 | 2866895 |
| experimental studies of seed predation in old-fields. | in a pair of experiments conducted in old-field habitats in southwestern michigan (usa), we examined rates of seed loss to post-dispersal predators (ants and rodents). seeds from 4-6 species of "biennial" plants were tested over a range of seed densities and habitat types. we found that seed removal was significantly higher in vegetated habitats than in areas of disturbed soil (both simulated small-animal diggings and a plowed field). in the undisturbed vegetation, seed losses ranged from 1-20% ... | 1984 | 28312102 |
| hypothyroidism in reproductively inhibited prairie deer mice (peromyscus maniculatus bairdi) from laboratory populations. | several thyroid function parameters were compared between reproductively inhibited prairie deer mice of both sexes taken from laboratory populations and corresponding reproductively capable controls. the results of these experiments indicated the following: 1) prairie deer mice females had a statistically significant daily variation in mean serum thyroxine concentration and males displayed a similar trend; 2) total serum thyroxine and triiodothyronine were significantly lower in both male and fe ... | 1984 | 6518231 |
| influence of melatonin on pubertal development in male deer mice (peromyscus maniculatus). | the role of melatonin in pubertal development was assessed in male deer mice (peromyscus maniculatus bairdii) exposed to photoperiodic and social stimuli. exogenous melatonin retarded puberty in males reared in a long photoperiod, but was without effect in males reared in short days. melatonin did not retard pubertal development induced by exposure of short-day males to an adult female. these results suggest that pineal melatonin mediates photoperiodic, but not social, control of pubertal develo ... | 1984 | 6512757 |
| effect of transitional photoperiods on testicular development and puberty in male deer mice (peromyscus maniculatus). | in a series of five experiments, young male deer mice (peromyscus maniculatus bairdii) were exposed to photoperiods ranging in length from 3 to 19 h per 24-h period, as well as to constant light and constant darkness. reproductive organ growth as measured at 6 weeks of age was inhibited by less than or equal to 11.5 h of light. in males receiving 11.5-19 h of light, there was a quantitative increase in reproductive organ size as a function of photoperiod. rather than a 'critical' photoperiod par ... | 1984 | 6512756 |
| photosensitive stages in pubertal development of male deer mice (peromyscus maniculatus). | male deer mice (peromyscus maniculatus bairdii) were exposed to a long (15l:9d) or short (6l:18d) photoperiod during four stages of development. at 6 weeks of postnatal age degree of pubertal development was determined by measurement of testis and seminal vesicle weights and area of the androgen-dependent sebaceous gland. continuous exposure to a short photoperiod beginning before conception (i.e. mother kept in short days), at conception, or at birth markedly retarded pubertal development. init ... | 1984 | 6512755 |
| involvement of the circadian system in photoperiodic control of pubertal development in female deer mice, peromyscus maniculatus. | pubertal development in female deer mice, peromyscus maniculatus, was stimulated by exposure to light cycles of ld 16:8, ld 6:30 or ld 6:54, but not by exposure to cycles of ld 6:18 or ld 6:42. these results support the hypothesis that female deer mice use a circadian rhythm of responsiveness to light to measure photoperiodic time. | 1984 | 6468610 |
| naloxone inhibition of stress-induced daily torpor. | peromyscus maniculatus, deermice , were induced into daily torpor by restricting food to one-half daily ration. intraperitoneal injection of naloxone (20 mg/kg) into mice habituated to daily ip injections of saline inhibited or modified the expression of daily torpor. in those individuals demonstrating long duration/deep bouts (greater than 300 min/body temperature 20 degrees c or below) naloxone administration resulted in 1) a significant decrease in the duration of torpor, 2) a significant ele ... | 1984 | 6727554 |
| maximum oxygen consumption during exercise and cold exposure in deer mice, peromyscus maniculatus. | convenient methods were developed for measuring maximum oxygen consumption (vo2 max) in untrained small mammals during treadmill exercise and cold exposure. deer mice (peromyscus maniculatus) were run once, for 6-min periods at velocities exceeding maximal aerobic running speed, while instantaneous oxygen consumption was measured. the vo2 max during cold exposure was determined using high wind speeds to increase heat loss rates. during running, the kinetics of gas exchange were rapid and similar ... | 1984 | 6739991 |
| normal testicular structure and reproductive function in deermice lacking retinol and alcohol dehydrogenase activity. | it was found that a strain of deermice (peromyscus maniculatus), which genetically lacks liver alcohol dehydrogenase activity also displays no such activity in the testis and is devoid of the enzyme activity that converts retinol to retinal, both in liver and in the testis; nevertheless, these animals exhibit normal reproduction and testicular histology. therefore, one must reconsider the theory that the testicular atrophy and aspermatogenesis commonly found in alcoholics is due, at least in par ... | 1984 | 6365975 |
| serum acth and adrenal histology in reproductively inhibited male prairie deermice (peromyscus maniculatus bairdi). | exogenous acth will cause adrenal hypertrophy and gonad dysfunction in reproductively capable male deermice. the ultrastructure of the zona fasciculata of inhibited animals is substantially different from acth stimulated animals which suggests that acth alone does not produce the inhibition. although acth concentrations were variable, there was no clear demonstration that any differences existed between reproductively capable vs inhibited animals at the time when corticosterone is known to be el ... | 1984 | 6146448 |
| a possible role for the thyroid in reproductive inhibition in laboratory populations of the prairie deermouse (peromyscus maniculatus). | serum thyroxine concentrations were determined and found to be reduced in reproductively inhibited deermice selected from controlled growth laboratory populations. daily injections of 1 microgram thyroxine in reproductively inhibited male deermice were shown to significantly increase testis weight and the number of spermatids with acrosome formation. daily feeding of thyroxine to a controlled growth population promoted an increase in the mean weights of the reproductive organs of both sexes that ... | 1984 | 6142798 |
| rhythms of barbiturate-induced sleep time in deermice entrained to non-twenty-four hour photocycles. | the present experiment examined whether entrainment to twenty-four hour days is advantageous for physiological and behavioral adaptations to a pharmacological challenge. adult, male deermice (peromyscus maniculatus) were injected with sodium pentobarbital at 8.5, 14.5, 20.5, 2.5 and again at 8.5 hr after light onset while entrained to a 24 hr day (light/dark (ld) 14:10). time to recover from anesthesia was recorded. subsequently, the dark phase of the ld cycle was reduced 15-20 min every 10 days ... | 1983 | 6635008 |
| influence of photoperiod and social environment on sexual maturation in female deer mice (peromyscus maniculatus bairdii). | female deer mice (peromyscus maniculatus) were reared on either a long photoperiod (15:9 hr light/dark) or on short days (8:16 hr light/dark) from birth. beginning at weaning, females were housed with an adult male, with an adult female, or in social isolation. in the first experiment, vaginas opened more slowly in females on short days than in those on long days. vaginal introitus was also retarded in females reared with an adult female in comparison with females reared in isolation. when exami ... | 1983 | 6872508 |
| gonadal hormone activation of male courtship ultrasonic vocalizations and male copulatory behavior in castrated male deer mice (peromyscus maniculatus bairdi). | the influence of testosterone (t), a 5 alpha-reduced metabolite of t, dihydrotestosterone, and an aromatized metabolite of t, estradiol, on 35-khz ultrasonic calling and male copulatory behavior by male deer mice (peromyscus maniculatus bairdi) was examined. daily treatment with testosterone propionate (tp), dihydrotestosterone propionate (dhtp), or estradiol benzoate (eb) restored male ultrasonic calling in long-term castrated males. both tp and dhtp restored male copulatory behavior, but eb wa ... | 1983 | 6871034 |
| selection components affecting hemoglobins in peromyscus maniculatus: a re-evaluation. | | 1983 | 28563308 |
| gametic selection and hemoglobin polymorphisms in peromyscus maniculatus: a rejoinder. | | 1983 | 28563302 |
| juvenile ataxia--a new behavioral mutation in the deermouse. | an autosomal recessive behavioral mutation designated juvenile ataxia (ja) was first isolated from f2 progeny of four blonde (bl) peromyscus maniculatus bairdi siblings. juvenile ataxic homozygotes exhibit an ataxic gait without an associated tremor from 15 days postpartum. this ataxia continues but does not increase noticeably in severity until between 35 and 43 days of age. thereafter, a rapid and dramatic improvement in the behavior pattern is seen, so that juvenile ataxic deermice over 45 da ... | 2003 | 6863895 |
| photoperiodic stimulation of pubertal development in male deer mice: involvement of the circadian system. | pubertal development in prairie deer mice (peromyscus maniculatus bairdii) is accelerated by exposure of juveniles to a long-day photoperiod, and, conversely, retarded by exposure to short days. the purpose of the present study was to evaluate the possible involvement of the circadian system in the photoperiodic regulation of puberty. weanling males, previously housed on a short-day light cycle of 6l:18d, were subjected to a "resonance" protocol in which they received one of the following light ... | 1983 | 6850042 |
| recovery from sexual satiety in deer mice (peromyscus maniculatus bairdi). | two experiments were completed in order to delineate the time course of recovery from sexual satiety in deer mice, peromyscus maniculatus bairdi. the total numbers of ejaculations and intromissions attained in satiety tests were significantly decreased on the day following satiation and recovered gradually as measured in tests run after 3 and 7 days of recovery. whereas some measures characteristic of individual series were altered by incomplete recovery, others were unaffected. in experiment 2, ... | 1983 | 6872505 |
| latitude of origin influences photoperiodic control of reproduction of deer mice (peromyscus maniculatus). | three subspecies of peromyscus maniculatus originating from different latitudes were maintained from birth in light dark cycles that provided between 10 and 18 h of light per day. at 50 days of age, chihuahua, mexico mice (latitude of origin 27 degrees n) and south dakota, u.s.a. mice (44 degrees n) kept in the 10l:14d photoperiod had reduced gonadal and seminal vesicle weights and a lower spermatogenic index than corresponding mice kept in a 14l:10d photoperiod. some chihuahua and south dakota ... | 1983 | 6681991 |
| extensive genetic variation in mitochondrial dna's among geographic populations of the deer mouse, peromyscus maniculatus. | | 1983 | 28568029 |
| immunological factors in peromyscus speciation. | reciprocal interspecific f1 hybrids of deermice (peromyscus maniculatus) and oldfield mice (p. polionotus) differ significantly and substantially in fetal and placental, as well as adult, size and weight. hybrid fetal mortality is associated with large conceptus size. skin grafts were exchanged between and within the two species to ascertain whether any relationship exists between mean graft retention time and body size of fetuses and adults. p. maniculatus skin grafted to p. polionotus rejected ... | 1982 | 6757375 |
| an assessment of "hidden" heterogeneity within electromorphs at three enzyme loci in deer mice. | allelic heterogeneity within protein electromorphs at three loci was examined in populations of deer mice (peromyscus maniculatus) collected from five localities across north america. we used a variety of electrophoretic techniques (including several starch and acrylamide conditions, gel-sieving, and isoelectric focusing) plus heat denaturation. of particular interest was the supernatant glutamate oxalate transaminase system (got-1; aspartate aminotransferase-1 of some authors), which under stan ... | 1982 | 7152246 |
| social stimulation of reproductive development in male deer mice housed on a short-day photoperiod. | male deer mice (peromyscus maniculatus), born of mothers housed on a long-day (ld) photoperiod (15:9 hr light/dark), were either switched to a short-day (sd) photoperiod (6:18 hr) at birth or continued on their prenatal ld photoperiod. from weaning until 6 wk of age, the males were housed either in cohabitation with an adult female or in social isolation. males reared on an sd photoperiod had smaller testes, seminal vesicles, and ventral sebaceous glands than did males reared on ld. postweaning ... | 1982 | 7096680 |
| testosterone acts as a prohormone to stimulate male copulatory behavior in male deer mice (peromyscus maniculatus bairdi). | in order to determine the importance of reduced and aromatized metabolites of testosterone for male sexual behavior in peromyscus maniculatus bairdi, castrated males were treated with 5 alpha-reductase and aromatase inhibitors. in the first experiment, testosterone propionate (tp) activation of male copulatory behavior was blocked by the administration of the 5 alpha-reductase inhibitor 4-androsten-3-one-17-beta carboxylic acid (17 beta c). these treatments also prevented tp stimulation of semin ... | 1982 | 7056894 |
| blonde, a new mutation in peromyscus maniculatus affecting fur, skin, and eye pigmentation. | an autosomal recessive mutation affecting hair and eye pigmentation was discovered in the f2 progeny of wild-type deer mice, (peromyscus maniculatus), trapped near east lansing, michigan. when homozygous, the mutation (designated as blonde, bl), reduces both black and yellow pigmentation deposited in the fur, reduces or eliminates pigmentation in the non-follicular melanocytes of the outer ear, peri-orbital skin and tail, slightly reduces the amount of pigmentation in the choroidal melanocytes, ... | 2003 | 7069191 |
| ultrasonic vocalizations in male deer mice (peromyscus maniculatus bairdi): their role in male sexual behavior. | | 1981 | 7323194 |
| male sexual behavior in deer mice (peromyscus maniculatus) following castration and hormone replacement. | | 1981 | 7250909 |
| selection components of four allozymes in natural populations of peromyscus maniculatus. | | 1981 | 28563465 |
| adult-young interactions in island and mainland populations of the deermouse peromyscus maniculatus. | the demographic and ecological characteristics of island populations of small mammals have received increasing attention in recent years, but few studies have compared the behavioral characteristics of island populations with those of mainland populations. behavior is considered an important variable because it is believed by many to be a crucial factor affecting the population dynamics and demography of natural populations. in particular, among many species of rodents, the social behavior of ad ... | 1981 | 28310030 |
| effects of urine from conspecifics on sexual maturation in female prairie deermice, peromyscus maniculatus bairdii. | | 1980 | 7217792 |
| modes of ectoparasite reinfestations of deer mice (peromyscus maniculatus). | modes of ectoparasite reinfestations were studied on ectoparasite-free deer mice (peromyscus maniculatus) returned to their natural habitat on the tule lake national wildlife refuge, siskiyou county, california, during the summer of 1977. the age of the host made no significant difference in the mode of reinfestation of lice, fleas, or mites. flea reinfestation rates were related to the sex of the host, requiring 4 and 2 days, respectively, to reach control levels on male and female hosts. mite ... | 1980 | 7463612 |
| social factors influencing delayed reproductive maturation in prairie deermice (peromyscus maniculatus bairdii) in laboratory populations. | | 1980 | 7462866 |
| cataract-webbed trait in peromyscus. ii. biomicroscopy and histology of eyes. | a longitudinal biomicroscopic study of lenses and fundi of over 2,000 peromyscus maniculatus (deer mice) which have cataracts as an autosomal recessive trait has been correlated with histologic development of cataracts. by selective breeding, early-onset cataracts (type i), which are frequently associated with abnormal closure of the fetal fissure and hyaloid vascular abnormalities, have been separated from later-onset (type ii) cataracts, which are more heterogeneous. type i cataracts occur in ... | 1980 | 7350132 |
| a study of the circadian rhythm and pre- and postpuberty concentrations of serum prolactin in male prairie deer mice (peromyscus maniculatus bairdii). | | 1979 | 499748 |
| reproductive failure and maternal-fetal relationship in a peromyscus species cross. | mating, fertilization, implantation, prenatal mortality, fetal and placental size, and placental ultrastructure were studied in intraspecific and interspecific crosses involving peromyscus maniculatus and p. polionotus. failure to mate was a major factor in interspecific crosses and was much more pronounced in crosses between p. polionotus females and p. maniculatus males than in the reciprocal cross. failure of implantation following mating, however, was more pronounced in crosses between p. ma ... | 1979 | 490135 |
| rodent housing units for field studies. | rodent housing and nesting units were constructed from acrylic and provided with concrete tops. these hexagonal units, placed in a wooded field, were inhabited by deer mice (peromyscus maniculatus). the use of the field housing units provided an effective method for observing free-ranging wild rodents. | 1979 | 459426 |
| the interaction of shivering and non-shivering thermogenesis in deer mice (peromyscus maniculatus). | | 1979 | 37038 |
| variation in the genetic structure of peromyscus populations. i. genetic heterozygosity--its relationship to adaptive divergence. | the genetic structure of nine peromyscus maniculatus nebrascensis demes from southeastern wyoming was determined by analyzing allozymes encoded by 23 genetic loci with polyacrylamide gel electrophoresis. genetic variability is extremely high for two genetic parameters; the proportion of loci polymorphic per deme averaged 0.41. previous estimates of genetic heterozygosity for species within the genus peromyscus have a mean of 0.06. the results of the present study suggest that genetic heterozygos ... | 1978 | 751646 |
| fractional factorial analysis of growth and weaning success in peromyscus maniculatus. | fractional factorial designs were used to explore simultaneously the effects of eight variables on survival and growth of neonatal deer mice, peromyscus maniculatus. two of the variables had significant effects on weaning success. the magnitudes of their effects are illustrated. | 1978 | 715451 |
| the existence of a puberty accelerating pheromone in the urine of the male prairie deermouse (peromyscus maniculatus bairdii). | | 1978 | 719090 |