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Shaikh N, Asif PY, Saltzman W. Inhibition of alloparental behavior by acute stress in virgin male California mice (Peromyscus californicus). Behav Processes 2024; 220:105060. [PMID: 38909665 DOI: 10.1016/j.beproc.2024.105060] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2024] [Revised: 05/08/2024] [Accepted: 06/13/2024] [Indexed: 06/25/2024]
Abstract
In many biparental mammals, such as California mice (Peromyscus californicus), fathers display affiliative behavior toward unfamiliar infants whereas reproductively naïve adult males show highly variable responses. Sources of this variability are not well understood, but evidence suggests that stress can either enhance or inhibit alloparental care. We evaluated immediate and delayed effects of acute stress on pup-directed behavior in adult virgin male California mice. Mice underwent three 10-minute tests with unfamiliar pups at 48-hour intervals. Stressed mice (N=22) received a subcutaneous oil injection immediately before tests 1 and 2, whereas controls (N=22) were left undisturbed. In controls, but not stressed mice, latency to approach the pup decreased and duration of alloparental behavior increased across the three tests. At each time point, stressed males were less likely than controls to perform alloparental behavior. Controls spent significantly more time performing alloparental behavior than stressed mice in tests 1 and 2 but not in test 3. Pup-directed aggression did not differ between the groups at any time point. These findings suggest that acute stress can both inhibit alloparental behavior in the short term and prevent the increase in alloparental behavior that typically occurs with repeated exposure to pups in virgin male California mice.
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Affiliation(s)
- Nabeel Shaikh
- Department of Evolution, Ecology, and Organismal Biology, University of California, Riverside, CA 92521, USA
| | - Parihan Y Asif
- Department of Evolution, Ecology, and Organismal Biology, University of California, Riverside, CA 92521, USA
| | - Wendy Saltzman
- Department of Evolution, Ecology, and Organismal Biology, University of California, Riverside, CA 92521, USA; Neuroscience Graduate Program, University of California, Riverside, CA 92521, USA.
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Harris BN, Roberts BR, DiMarco GM, Maldonado KA, Okwunwanne Z, Savonenko AV, Soto PL. Hypothalamic-pituitary-adrenal (HPA) axis activity and anxiety-like behavior during aging: A test of the glucocorticoid cascade hypothesis in amyloidogenic APPswe/PS1dE9 mice. Gen Comp Endocrinol 2023; 330:114126. [PMID: 36122793 PMCID: PMC10250074 DOI: 10.1016/j.ygcen.2022.114126] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/02/2022] [Revised: 09/06/2022] [Accepted: 09/13/2022] [Indexed: 12/14/2022]
Abstract
Alzheimer's disease (AD) is a progressive, dementing, whole-body disorder that presents with decline in cognitive, behavioral, and emotional functions, as well as endocrine dysregulation. The etiology of AD is not fully understood but stress- and anxiety-related hormones may play a role in its development and trajectory. The glucocorticoid cascade hypothesis posits that levels of glucocorticoids increase with age, leading to dysregulated negative feedback, further elevated glucocorticoids, and resulting neuropathology. We examined the impact of age (from 2 to 10 months) and stressor exposure (predator odor) on hormone levels (corticosterone and ghrelin), anxiety-like behavior (open field and light dark tests), and memory-related behavior (novel object recognition; NOR), and whether these various measures correlated with neuropathology (hippocampus and cortex amyloid beta, Aβ) in male and female APPswe/PS1dE9 transgenic and non-transgenic mice. Additionally, we performed exploratory analyses to probe if the open field and light dark test as commonly used tasks to assess anxiety levels were correlated. Consistent with the glucocorticoid cascade hypothesis, baseline corticosterone increased with age. Predator odor exposure elevated corticosterone at each age, but in contrast to the glucocorticoid cascade hypothesis, the magnitude of stressor-induced elevations in corticosterone levels did not increase with age. Overall, transgenic mice had higher post-stressor, but not baseline, corticosterone than non-transgenic mice, and across both genotypes, females consistently had higher (baseline and post-stressor) corticosterone than males. Behavior in the open field test primarily showed decreased locomotion with age, and this was pronounced in transgenic females. Anxiety-like behaviors in the light dark test were exacerbated following predator odor, and female transgenic mice were the most impacted. Compared to transgenic males, transgenic females had higher Aβ concentrations and showed more anxiety-like behavior. Performance on the NOR did not differ significantly between genotypes. Lastly, we did not find robust, statistically significant correlations among corticosterone, ghrelin, recognition memory, anxiety-like behaviors, or Aβ, suggesting outcomes are not strongly related on the individual level. Our data suggest that despite Aβ accumulation in the hippocampus and cortex, male and female APPswePS1dE9 transgenic mice do not differ robustly from their non-transgenic littermates in physiological, endocrine, and behavioral measures at the range of ages studied here.
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Affiliation(s)
- Breanna N Harris
- Department of Biological Sciences, Texas Tech University, Lubbock, TX, United States.
| | - Breanna R Roberts
- Department of Biological Sciences, Texas Tech University, Lubbock, TX, United States
| | - Giuliana M DiMarco
- Department of Biological Sciences, Texas Tech University, Lubbock, TX, United States; Center for Molecular and Behavioral Neuroscience, Rutgers, The State University of New Jersey, Newark, NJ, United States
| | | | - Zenobia Okwunwanne
- Department of Biological Sciences, Texas Tech University, Lubbock, TX, United States
| | - Alena V Savonenko
- Department of Pathology, The Johns Hopkins University School of Medicine, Baltimore, MD, United States; Department of Neurology, The Johns Hopkins University School of Medicine, Baltimore, MD, United States
| | - Paul L Soto
- Department of Psychology, Louisiana State University, Baton Rouge, LA, United States
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Wilson KM, Wagner VA, Saltzman W. Specificity of California mouse pup vocalizations in response to olfactory stimuli. Dev Psychobiol 2022; 64:e22261. [DOI: 10.1002/dev.22261] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2021] [Revised: 01/07/2022] [Accepted: 01/18/2022] [Indexed: 11/06/2022]
Affiliation(s)
- Kerianne M. Wilson
- Department of Evolution, Ecology, and Organismal Biology University of California Riverside Riverside California USA
| | - Victoria A. Wagner
- Graduate Program in Neuroscience University of California Riverside Riverside California USA
| | - Wendy Saltzman
- Department of Evolution, Ecology, and Organismal Biology University of California Riverside Riverside California USA
- Graduate Program in Neuroscience University of California Riverside Riverside California USA
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Ogbonna AC, Chaudhry AS, Asher L. Effect of Dietary Vitamin D3 and Ultraviolet B Light on Growth Performance, Blood Serum Parameters, Gut Histology, and Welfare Indicators of Broilers. FRONTIERS IN ANIMAL SCIENCE 2022. [DOI: 10.3389/fanim.2021.806967] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Stressors are commonly encountered by all farmed species, including chickens, but the impact of these stressors on the animal and their productivity can be influenced by the environmental conditions in which they are kept. This study investigated the effects of dietary vitamin D3 (vitD3) and ultraviolet light (UVB) on growth performance, organ weight, serum corticosterone levels (CORT), serum 25-hydroxy vitamin D (25-OH-D3) status, gut histology, and welfare indicators of broiler chickens challenged with social isolation stress. One day (d) old Ross 308 broiler chicks (n = 192) were individually weighed, wing-tagged, and allocated to non-isolated (control) and isolated groups; control birds were never isolated, while isolated birds were subjected to regular sessions of social isolation for about 15-min periods over the course of 3 d a week for 2 weeks starting from d 10 (1.30 h total exposure) with inter treatment interval of 48 h. Birds were treated with either dietary vitD3 at 4,000 IU/kg (HD) or UVB light (UVB). The UVB lamp (24 Watt 12% UVB D3, 55 cm) with wavelength: 280–315 nm, intensity; 28.12 μW/cm2 hung 50 cm above the substrate was used for the broilers in all the treatment groups but were filtered to remove UVB in the HD group. Growth performance measure; body weight gain, feed intake, and feed conversion ratio were estimated at the end of starter (day 10), grower (day 24), and finisher periods (day 38). Broilers were feather and gait scored to measure welfare at 22/35 and 24/37 days of age, respectively. The selected birds were weighed and euthanized to obtain serum to determine 25-OH-D3 and CORT levels, GIT weights, and gut histology. Subjecting the birds to 2-week social isolation (for 15 min, three times per week) increased CORT levels but did not alter GP and 25-OH-D3 levels of broilers. However, UVB-treated broilers demonstrated better welfare, duodenal absorptive capacity, and reduced FCR compared to HD chickens. Results suggest some beneficial effects of UVB lighting on welfare indicators and the potential to support early life growth of commercial broilers reared indoors, which are often challenged with stressors.
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Horrell ND, Acosta MC, Saltzman W. Plasticity of the paternal brain: Effects of fatherhood on neural structure and function. Dev Psychobiol 2021; 63:1499-1520. [PMID: 33480062 PMCID: PMC8295408 DOI: 10.1002/dev.22097] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2020] [Revised: 12/14/2020] [Accepted: 12/23/2020] [Indexed: 12/12/2022]
Abstract
Care of infants is a hallmark of mammals. Whereas parental care by mothers is obligatory for offspring survival in virtually all mammals, fathers provide care for their offspring in only an estimated 5%-10% of genera. In these species, the transition into fatherhood is often accompanied by pronounced changes in males' behavioral responses to young, including a reduction in aggression toward infants and an increase in nurturant behavior. The onset of fatherhood can also be associated with sensory, affective, and cognitive changes. The neuroplasticity that mediates these changes is not well understood; however, fatherhood can alter the production and survival of new neurons; function and structure of existing neurons; morphology of brain structures; and neuroendocrine signaling systems. Although these changes are thought to promote infant care by fathers, very little evidence exists to support this hypothesis; in most cases, neither the mechanisms underlying neuroplasticity in fathers nor its functional significance is known. In this paper, we review the available data on the neuroplasticity that occurs during the transition into fatherhood. We highlight gaps in our knowledge and future directions that will provide key insights into how and why fatherhood alters the structure and functioning of the male brain.
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Affiliation(s)
| | - Melina C. Acosta
- Graduate Program in Neuroscience and Department of Evolution, Ecology, and Organismal Biology, University of California, Riverside, CA USA
| | - Wendy Saltzman
- Graduate Program in Neuroscience and Department of Evolution, Ecology, and Organismal Biology, University of California, Riverside, CA USA
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An acute dose of intranasal oxytocin rapidly increases maternal communication and maintains maternal care in primiparous postpartum California mice. PLoS One 2021; 16:e0244033. [PMID: 33886559 PMCID: PMC8061985 DOI: 10.1371/journal.pone.0244033] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2020] [Accepted: 04/05/2021] [Indexed: 12/29/2022] Open
Abstract
Maternal-offspring communication and care are essential for offspring survival. Oxytocin (OXT) is known for its role in initiation of maternal care, but whether OXT can rapidly influence maternal behavior or ultrasonic vocalizations (USVs; above 50 kHz) has not been examined. To test for rapid effects of OXT, California mouse mothers were administered an acute intranasal (IN) dose of OXT (0.8 IU/kg) or saline followed by a separation test with three phases: habituation with pups in a new testing chamber, separation via a wire mesh, and finally reunion with pups. We measured maternal care, maternal USVs, and pup USVs. In mothers, we primarily observed simple sweep USVs, a short downward sweeping call around 50 kHz, and in pups we only observed pup whines, a long call with multiple harmonics ranging from 20 kHz to 50 kHz. We found that IN OXT rapidly and selectively enhanced the normal increase in maternal simple sweep USVs when mothers had physical access to pups (habituation and reunion), but not when mothers were physically separated from pups. Frequency of mothers’ and pups’ USVs were correlated upon reunion, but IN OXT did not influence this correlation. Finally, mothers given IN OXT showed more efficient pup retrieval/carrying and greater total maternal care upon reunion. Behavioral changes were specific to maternal behaviors (e.g. retrievals) as mothers given IN OXT did not differ from controls in stress-related behaviors (e.g. freezing). Overall, these findings highlight the rapid effects and context-dependent effect a single treatment with IN OXT has on both maternal USV production and offspring care.
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Andrew JR, Garland T, Chappell MA, Zhao M, Horrell ND, Saltzman W. Long-Term Effects of Fatherhood on Morphology, Energetics, and Exercise Performance in California Mice ( Peromyscus californicus). Physiol Biochem Zool 2020; 93:75-86. [PMID: 31808736 DOI: 10.1086/706863] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
In male mammals that provide care for their offspring, fatherhood can lead to changes in behavioral, morphological, and physiological traits, some of which might constitute trade-offs. However, relatively little is known about these changes, especially across multiple reproductive bouts, which are expected to magnify differences between fathers and nonreproductive males. We evaluated consequences of fatherhood in the monogamous, biparental California mouse (Peromsycus californicus) across seven consecutive reproductive bouts. We compared breeding adult males (housed with sham-ovariectomized females) with two control groups: nonbreeding males (housed with ovariectomized females treated with estrogen and progesterone to induce estrous behavior) and virgin males (housed with untreated ovariectomized females). At five time points (before pairing, early postpartum of the first litter, late postpartum of the second litter, early postpartum of the sixth litter, and late postpartum of the seventh litter or comparable time points for nonbreeding and virgin males), we measured males' body composition, hematocrit, predatory aggression, resting metabolic rate, maximal oxygen consumption (V˙O2 max), grip strength, and sprint speed. We also weighed organs at the final time point. We predicted that fathers would have lower relative body fat and lower performance abilities compared with control groups and that these effects would become more pronounced with increasing parity. Contrary to predictions, breeding and control males differed in surprisingly few measures, and the number and magnitude of differences did not increase with parity. Thus, our expectations regarding trade-offs were not met. As reported in studies of single reproductive events, these results suggest that fatherhood has few costs in this species when housed under standard laboratory conditions, even across multiple reproductive bouts.
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Andrew JR, Garland T, Chappell MA, Zhao M, Saltzman W. Effects of short- and long-term cold acclimation on morphology, physiology, and exercise performance of California mice (Peromyscus californicus): potential modulation by fatherhood. J Comp Physiol B 2019; 189:471-487. [PMID: 31073767 PMCID: PMC6667301 DOI: 10.1007/s00360-019-01219-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2018] [Revised: 03/27/2019] [Accepted: 04/22/2019] [Indexed: 01/23/2023]
Abstract
California mice (Peromyscus californicus) differ from most other mammals in that they are biparental, genetically monogamous, and (compared with other Peromyscus) relatively large. We evaluated effects of cold acclimation on metabolic rate, exercise performance, and morphology of pair-housed male California mice, as well as modulation of these effects by fatherhood. In Experiment 1, virgin males housed at 5° or 10 °C for approximately 25 days were compared with virgins housed at standard vivarium temperature of 22 °C. Measures included resting metabolic rate (RMR), maximal oxygen consumption ([Formula: see text]max), grip strength, and sprint speed. In Experiment 2, virgin males housed at 22 °C were compared with three groups of males housed at 10 °C: virgins, breeding males (housed with a female and their pups), and non-breeding males (housed with an ovariectomized, estrogen- and progesterone-treated female) after long-term acclimation (mean 243 days). Measures in this experiment included basal metabolic rate (BMR), [Formula: see text]max, maximal thermogenic capacity ([Formula: see text]sum), and morphological traits. In Experiment 1, virgin males housed at 5° and 10 °C had higher RMR and [Formula: see text]max than those at 22 °C. In Experiment 2, 10 °C-acclimated groups had shorter bodies; increased body, fat, and lean masses; higher BMR and [Formula: see text]sum, and generally greater morphometric measures and organ masses than virgin males at 22 °C. Among the groups housed at 10 °C, breeding males had higher BMR and lower [Formula: see text]max than non-breeding and/or virgin males. Overall, we found that effects of fatherhood during cold acclimation were inconsistent, and that several aspects of cold acclimation differ substantially between California mice and other small mammals.
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Affiliation(s)
- Jacob R Andrew
- Department of Evolution, Ecology, and Organismal Biology, University of California, Riverside, Riverside, CA, 92521, USA
- Department of Obstetrics, Gynecology and Reproductive Sciences, Moores Cancer Center, University of California, San Diego, La Jolla, CA, 92037, USA
| | - Theodore Garland
- Department of Evolution, Ecology, and Organismal Biology, University of California, Riverside, Riverside, CA, 92521, USA
| | - Mark A Chappell
- Department of Evolution, Ecology, and Organismal Biology, University of California, Riverside, Riverside, CA, 92521, USA
| | - Meng Zhao
- Department of Evolution, Ecology, and Organismal Biology, University of California, Riverside, Riverside, CA, 92521, USA
- Department of Pathology, Stanford University School of Medicine, Stanford, CA, 94305, USA
| | - Wendy Saltzman
- Department of Evolution, Ecology, and Organismal Biology, University of California, Riverside, Riverside, CA, 92521, USA.
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Zhao M, Harris BN, Nguyen CTY, Saltzman W. Effects of single parenthood on mothers' behavior, morphology, and endocrine function in the biparental California mouse. Horm Behav 2019; 114:104536. [PMID: 31153926 DOI: 10.1016/j.yhbeh.2019.05.005] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/15/2018] [Revised: 03/31/2019] [Accepted: 05/24/2019] [Indexed: 12/29/2022]
Abstract
Motherhood is energetically costly for mammals and is associated with pronounced changes in mothers' physiology, morphology and behavior. In ~5% of mammals, fathers assist their mates with rearing offspring and can enhance offspring survival and development. Although these beneficial consequences of paternal care can be mediated by direct effects on offspring, they might also be mediated indirectly, through beneficial effects on mothers. We tested the hypothesis that fathers in the monogamous, biparental California mouse (Peromyscus californicus) reduce the burden of parental care on their mates, and therefore, that females rearing offspring with and without assistance from their mates will show differences in endocrinology, morphology and behavior, as well as in the survival and development of their pups. We found that pups' survival and development in the lab did not differ between those raised by a single mother and those reared by both mother and father. Single mothers spent more time in feeding behaviors than paired mothers. Both single and paired mothers had higher lean mass and/or lower fat mass and showed more anxiety-like behavior in open-field tests and tail-suspension tests, compared to non-breeding females. Single mothers had higher body-mass-corrected liver and heart masses, but lower ovarian and uterine masses, than paired mothers and/or non-breeding females. Mass of the gastrointestinal tract did not differ between single and paired mothers, but single mothers had heavier gastrointestinal tract compared to non-breeding females. Single motherhood also induced a flattened diel corticosterone rhythm and a blunted corticosterone response to stress, compared to non-breeding conditions. These findings suggest that the absence of a mate induces morphological and endocrine changes in mothers, which might result from increased energetic demands of pup care and could potentially help maintain normal survival and development of pups.
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Affiliation(s)
- Meng Zhao
- Department of Evolution, Ecology, and Organismal Biology, University of California, Riverside, United States of America
| | - Breanna N Harris
- Department of Biological Sciences, Texas Tech University, United States of America
| | - Catherine T Y Nguyen
- Department of Evolution, Ecology, and Organismal Biology, University of California, Riverside, United States of America
| | - Wendy Saltzman
- Department of Evolution, Ecology, and Organismal Biology, University of California, Riverside, United States of America.
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Seelke AMH, Bond JM, Simmons TC, Joshi N, Settles ML, Stolzenberg D, Rhemtulla M, Bales KL. Fatherhood alters gene expression within the MPOA. ENVIRONMENTAL EPIGENETICS 2018; 4:dvy026. [PMID: 30568805 PMCID: PMC6305489 DOI: 10.1093/eep/dvy026] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/24/2018] [Revised: 10/03/2018] [Accepted: 10/19/2018] [Indexed: 06/09/2023]
Abstract
Female parenting is obligate in mammals, but fathering behavior among mammals is rare. Only 3-5% of mammalian species exhibit biparental care, including humans, and mechanisms of fathering behavior remain sparsely studied. However, in species where it does exist, paternal care is often crucial to the survivorship of offspring. The present study is the first to identify new gene targets linked to the experience of fathering behavior in a biparental species using RNA sequencing. In order to determine the pattern of gene expression within the medial preoptic area that is specifically associated with fathering behavior, we identified genes in male prairie voles (Microtus ochrogaster) that experienced one of three social conditions: virgin males, pair bonded males, and males with fathering experience. A list of genes exhibiting different expression patterns in each comparison (i.e. Virgin vs Paired, Virgin vs Fathers, and Paired vs Fathers) was evaluated using the gene ontology enrichment analysis, and Kyoto Encyclopedia of Genes and Genomes pathways analysis to reveal metabolic pathways associated with specific genes. Using these tools, we generated a filtered list of genes that exhibited altered patterns of expression in voles with different amounts of social experience. Finally, we used NanoString to quantify differences in the expression of these selected genes. These genes are involved in a variety of processes, with enrichment in genes associated with immune function, metabolism, synaptic plasticity, and the remodeling of dendritic spines. The identification of these genes and processes will lead to novel insights into the biological basis of fathering behavior.
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Affiliation(s)
- Adele M H Seelke
- Department of Psychology, University of California, Davis, Davis, USA
| | - Jessica M Bond
- Department of Psychology, University of California, Davis, Davis, USA
| | - Trent C Simmons
- Department of Psychology, University of California, Davis, Davis, USA
| | - Nikhil Joshi
- Bioinformatics Core Facility, University of California, Davis, Davis, USA
| | - Matthew L Settles
- Bioinformatics Core Facility, University of California, Davis, Davis, USA
| | | | - Mijke Rhemtulla
- Department of Psychology, University of California, Davis, Davis, USA
| | - Karen L Bales
- Department of Psychology, University of California, Davis, Davis, USA
- California National Primate Research Center, University of California, Davis, Davis, USA
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Bairos-Novak KR, Ryan CP, Freeman AR, Anderson WG, Hare JF. Like mother, like daughter: heritability of female Richardson's ground squirrel Urocitellus richardsonii cortisol stress responses. Curr Zool 2018; 64:153-163. [PMID: 30402055 PMCID: PMC5905375 DOI: 10.1093/cz/zox014] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2017] [Accepted: 02/22/2017] [Indexed: 11/16/2022] Open
Abstract
Activation of the hypothalamic-pituitary-adrenal (HPA) axis liberates glucocorticoids, which provides an acute indication of an individual's response to stressors. The heritability of the stress response in wild mammals, however, remains poorly documented. We quantified the cortisol stress response of female Richardson's ground squirrels (RGSs) to handling and physical restraint, testing for: (1) the effects of individual age, time of day, and sample latency; (2) repeatability within individuals; (3) narrow-sense heritability; and (4) differences among individuals owing to potential genetic and/or environmental effects. We detected a positive linear relationship between baseline plasma cortisol (BL-cortisol) concentration and stress-induced plasma cortisol (SI-cortisol) concentration that defined each individual's cortisol stress response. BL-cortisol, SI-cortisol, and stress response did not differ according to the time the sample was taken, or by subject age. Cortisol stress response was highly repeatable within individuals, had a mother-offspring heritability of h 2 = 0.40 ± 0.24 (mean ± SE), full-sibling heritability ofh FS 2 = 0.37 ± 0.71 , and half-sibling heritability ofh HS 2 = 0.75 ± 1.41 . Stress responses of sibling groups, immediate-family groups, and squirrels within a given area did not differ, whereas those of individuals from more distantly related matrilines did. Our results highlight the natural variability in HPA axis reactivity among individuals by quantifying both BL- and SI-cortisol levels, demonstrate partial heritability of the stress response that is not attributable to environmental variation, and suggest that at least part of an individual's stress response can be accounted for by differences in matrilineal history.
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Affiliation(s)
- Kevin R Bairos-Novak
- Department of Biological Sciences, University of Manitoba, Winnipeg, Manitoba, R3T 2N2, Canada
- Department of Biology, University of Saskatchewan, Saskatoon, S7N 5E2 Saskatchewan, Canada
| | - Calen P Ryan
- Department of Biological Sciences, University of Manitoba, Winnipeg, Manitoba, R3T 2N2, Canada
- Department of Anthropology, Northwestern University, Evanston, 60208 Illinois, USA
| | - Angela R Freeman
- Department of Biological Sciences, University of Manitoba, Winnipeg, Manitoba, R3T 2N2, Canada
- Department of Biological Sciences, Kent State University, Kent, 44242 Ohio, USA
| | - W Gary Anderson
- Department of Biological Sciences, University of Manitoba, Winnipeg, Manitoba, R3T 2N2, Canada
| | - James F Hare
- Department of Biological Sciences, University of Manitoba, Winnipeg, Manitoba, R3T 2N2, Canada
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Zhao M, Garland T, Chappell MA, Andrew JR, Harris BN, Saltzman W. Effects of a physical and energetic challenge on male California mice ( Peromyscus californicus): modulation by reproductive condition. ACTA ACUST UNITED AC 2018; 221:jeb.168559. [PMID: 29170256 DOI: 10.1242/jeb.168559] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2017] [Accepted: 11/14/2017] [Indexed: 12/13/2022]
Abstract
Reproduction strongly influences metabolism, morphology and behavior in female mammals. In species in which males provide parental care, reproduction might have similar effects on fathers. We examined effects of an environmental challenge on metabolically important physiological, morphological and behavioral measures, and determined whether these effects differed between reproductive and non-reproductive males in the biparental California mouse (Peromyscus californicus). Males were paired with an ovary-intact female, an ovariectomized female treated with estrogen and progesterone to induce estrus, or an untreated ovariectomized female. Within each group, half of the animals were housed under standard laboratory conditions and half in cages requiring them to climb wire towers to obtain food and water; these latter animals were also fasted for 24 h every third day. We predicted that few differences would be observed between fathers and non-reproductive males under standard conditions, but that fathers would be in poorer condition than non-reproductive males under challenging conditions. Body and fat mass showed a housing condition×reproductive group interaction: the challenge condition increased body and fat mass in both groups of non-reproductive males, but breeding males were unaffected. Males housed under the physical and energetic challenge had higher blood lipid content, lower maximal aerobic capacity and related traits (hematocrit and relative triceps surae mass), increased pain sensitivity and increased number of fecal boli excreted during tail-suspension tests (a measure of anxiety), compared with controls. Thus, our physical and energetic challenge paradigm altered metabolism, morphology and behavior, but these effects were largely unaffected by reproductive condition.
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Affiliation(s)
- Meng Zhao
- Department of Evolution, Ecology, and Organismal Biology, University of California, Riverside, CA 92521, USA
| | - Theodore Garland
- Department of Evolution, Ecology, and Organismal Biology, University of California, Riverside, CA 92521, USA
| | - Mark A Chappell
- Department of Evolution, Ecology, and Organismal Biology, University of California, Riverside, CA 92521, USA
| | - Jacob R Andrew
- Department of Evolution, Ecology, and Organismal Biology, University of California, Riverside, CA 92521, USA
| | - Breanna N Harris
- Department of Biological Sciences, Texas Tech University, Lubbock, TX 79409, USA
| | - Wendy Saltzman
- Department of Evolution, Ecology, and Organismal Biology, University of California, Riverside, CA 92521, USA
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Horrell ND, Hickmott PW, Saltzman W. Neural Regulation of Paternal Behavior in Mammals: Sensory, Neuroendocrine, and Experiential Influences on the Paternal Brain. Curr Top Behav Neurosci 2018; 43:111-160. [PMID: 30206901 DOI: 10.1007/7854_2018_55] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Across the animal kingdom, parents in many species devote extraordinary effort toward caring for offspring, often risking their lives and exhausting limited resources. Understanding how the brain orchestrates parental care, biasing effort over the many competing demands, is an important topic in social neuroscience. In mammals, maternal care is necessary for offspring survival and is largely mediated by changes in hormones and neuropeptides that fluctuate massively during pregnancy, parturition, and lactation (e.g., progesterone, estradiol, oxytocin, and prolactin). In the relatively small number of mammalian species in which parental care by fathers enhances offspring survival and development, males also undergo endocrine changes concurrent with birth of their offspring, but on a smaller scale than females. Thus, fathers additionally rely on sensory signals from their mates, environment, and/or offspring to orchestrate paternal behavior. Males can engage in a variety of infant-directed behaviors that range from infanticide to avoidance to care; in many species, males can display all three behaviors in their lifetime. The neural plasticity that underlies such stark changes in behavior is not well understood. In this chapter we summarize current data on the neural circuitry that has been proposed to underlie paternal care in mammals, as well as sensory, neuroendocrine, and experiential influences on paternal behavior and on the underlying circuitry. We highlight some of the gaps in our current knowledge of this system and propose future directions that will enable the development of a more comprehensive understanding of the proximate control of parenting by fathers.
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Affiliation(s)
- Nathan D Horrell
- Graduate Program in Neuroscience, University of California, Riverside, Riverside, CA, USA
- Department of Evolution, Ecology, and Organismal Biology, University of California, Riverside, Riverside, CA, USA
| | - Peter W Hickmott
- Graduate Program in Neuroscience, University of California, Riverside, Riverside, CA, USA
- Department of Psychology, University of California, Riverside, Riverside, CA, USA
| | - Wendy Saltzman
- Graduate Program in Neuroscience, University of California, Riverside, Riverside, CA, USA.
- Department of Evolution, Ecology, and Organismal Biology, University of California, Riverside, Riverside, CA, USA.
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14
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Zhao M, Garland T, Chappell MA, Andrew JR, Saltzman W. Metabolic and affective consequences of fatherhood in male California mice. Physiol Behav 2017; 177:57-67. [PMID: 28414073 DOI: 10.1016/j.physbeh.2017.04.010] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2016] [Revised: 03/10/2017] [Accepted: 04/12/2017] [Indexed: 01/06/2023]
Abstract
Physiological and affective condition can be modulated by the social environment and parental state in mammals. However, in species in which males assist with rearing offspring, the metabolic and affective effects of pair bonding and fatherhood on males have rarely been explored. In this study we tested the hypothesis that fathers, like mothers, experience energetic costs as well as behavioral and affective changes (e.g., depression, anxiety) associated with parenthood. We tested this hypothesis in the monogamous, biparental California mouse (Peromyscus californicus). Food intake, blood glucose and lipid levels, blood insulin and leptin levels, body composition, pain sensitivity, and depression-like behavior were compared in males from three reproductive groups: virgin males (VM, housed with another male), non-breeding males (NB, housed with a tubally ligated female), and breeding males (BM, housed with a female and their first litter). We found statistically significant (P<0.007, when modified for Adaptive False Discovery Rate) or nominally significant (0.007<P<0.05) differences among reproductive groups in relative testis mass, circulating glucose, triglyceride, and insulin concentrations, pain sensitivity, and anxiety-like behaviors. A priori contrasts indicated that VM produced significantly more fecal pellets than BM in the tail-suspension test, had significantly higher glucose levels than NB, and had significantly lower average testis masses than did NB and BM. A priori contrasts also indicated that VM had a nominally longer latency to the pain response than NB and that VM had nominally higher insulin levels than did NB. For breeding males, litter size (one to three pups) was a nominally significant positive predictor of body mass, food consumption, fat mass, and plasma leptin concentration. These results indicate that cohabitation with a female and/or fatherhood influences several metabolic, morphological, and affective measures in male California mice. Overall, the changes we observed in breeding males were minor, but stronger effects might occur in long-term breeding males and/or under more challenging environmental conditions.
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Affiliation(s)
- Meng Zhao
- Department of Biology, University of California, Riverside, USA; Evolution, Ecology and Organismal Biology Graduate Program, University of California, Riverside, USA
| | - Theodore Garland
- Department of Biology, University of California, Riverside, USA; Evolution, Ecology and Organismal Biology Graduate Program, University of California, Riverside, USA
| | - Mark A Chappell
- Department of Biology, University of California, Riverside, USA; Evolution, Ecology and Organismal Biology Graduate Program, University of California, Riverside, USA
| | - Jacob R Andrew
- Department of Biology, University of California, Riverside, USA; Evolution, Ecology and Organismal Biology Graduate Program, University of California, Riverside, USA
| | - Wendy Saltzman
- Department of Biology, University of California, Riverside, USA; Evolution, Ecology and Organismal Biology Graduate Program, University of California, Riverside, USA.
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15
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Horrell ND, Perea-Rodriguez JP, Harris BN, Saltzman W. Effects of repeated pup exposure on behavioral, neural, and adrenocortical responses to pups in male California mice (Peromyscus californicus). Horm Behav 2017; 90:56-63. [PMID: 28232065 PMCID: PMC5410176 DOI: 10.1016/j.yhbeh.2017.02.008] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/24/2016] [Revised: 02/11/2017] [Accepted: 02/17/2017] [Indexed: 12/28/2022]
Abstract
In biparental mammals, the factors facilitating the onset of male parental behavior are not well understood. While hormonal changes in fathers may play a role, prior experience with pups has also been implicated. We evaluated effects of prior exposure to pups on paternal responsiveness in the biparental California mouse (Peromyscus californicus). We analyzed behavioral, neural, and corticosterone responses to pups in adult virgin males that were interacting with a pup for the first time, adult virgin males that had been exposed to pups 3 times for 20min each in the previous week, and new fathers. Control groups of virgins were similarly tested with a novel object (marble). Previous exposure to pups decreased virgins' latency to approach pups and initiate paternal care, and increased time spent in paternal care. Responses to pups did not differ between virgins with repeated exposure to pups and new fathers. In contrast, repeated exposure to a marble had no effects. Neither basal corticosterone levels nor corticosterone levels following acute pup or marble exposure differed among groups. Finally, Fos expression in the medial preoptic area, ventral and dorsal bed nucleus of the stria terminalis was higher following exposure to a pup than to a marble. Fos expression was not, however, affected by previous exposure to these stimuli. These results suggest that previous experience with pups can facilitate the onset of parental behavior in male California mice, similar to findings in female rodents, and that this effect is not associated with a general reduction in neophobia.
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Affiliation(s)
- Nathan D Horrell
- Graduate Program in Neuroscience, University of California, Riverside, United States; Department of Biology, University of California, Riverside, United States
| | - Juan P Perea-Rodriguez
- Department of Biology, University of California, Riverside, United States; Evolution, Ecology, and Organismal Biology Graduate Program, University of California, Riverside, United States
| | - Breanna N Harris
- Department of Biological Sciences, Texas Tech University, United States
| | - Wendy Saltzman
- Graduate Program in Neuroscience, University of California, Riverside, United States; Department of Biology, University of California, Riverside, United States; Evolution, Ecology, and Organismal Biology Graduate Program, University of California, Riverside, United States.
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16
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de Bruin R, Ganswindt A, le Roux A. From killer to carer: steroid hormones and paternal behaviour. AFRICAN ZOOLOGY 2016. [DOI: 10.1080/15627020.2016.1258327] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Affiliation(s)
- Ruan de Bruin
- Mammalian Cognition Research Group, Department of Zoology and Entomology, University of the Free State, Qwaqwa campus, Phuthaditjhaba, South Africa
| | - Andre Ganswindt
- Department of Anatomy and Physiology, Faculty of Veterinary Science, University of Pretoria, Onderstepoort, South Africa
| | - Aliza le Roux
- Mammalian Cognition Research Group, Department of Zoology and Entomology, University of the Free State, Qwaqwa campus, Phuthaditjhaba, South Africa
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17
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Orikasa C, Kondo Y, Katsumata H, Terada M, Akimoto T, Sakuma Y, Minami S. Vomeronasal signal deficiency enhances parental behavior in socially isolated male mice. Physiol Behav 2016; 168:98-102. [PMID: 27840094 DOI: 10.1016/j.physbeh.2016.11.004] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2016] [Revised: 11/08/2016] [Accepted: 11/08/2016] [Indexed: 11/26/2022]
Abstract
We previously reported that social isolation promotes parental care in sexually naïve male mice. This effect was blocked by exposure to chemosensory and auditory social signals derived from males in an adjacent compartment. In the present study, we examined whether the chemosensory signals detected in the vomeronasal organ (VNO) are involved in parental behavior by using mice deficient for a VNO-specific ion channel (Trpc2-/-) and thus impaired in VNO-input signaling. We housed virgin homozygous Trpc2-/- and heterozygous Trpc2± males for 3weeks during puberty (5-8weeks old) alone or in groups of 3-5 males. At 8weeks of age, the mice were placed with three pups in an observation cage and tested for parental behavior. The Trpc2-/- males housed under isolated conditions spent significantly longer in the vicinity of pups than did the Trpc2-/- males than had been group housed, whereas no isolation effect was observed in heterozygous Trpc2± males. Both Trpc2 knockout and isolation housing significantly increased the time males spent licking pups and crouching (arched back posture over pups to enable nursing), whereas only isolation housing increased the incidence of retrieval behavior. These results demonstrated that social signals transmitted not only through the VNO but also from other modalities, independent of each other, suppress the expression of parental behavior during puberty in sexually naïve males.
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Affiliation(s)
- Chitose Orikasa
- Institute for Advanced Medical Sciences, Nippon Medical School, Kanagawa 211-8533, Japan.
| | - Yasuhiko Kondo
- Department of Animal Sciences, Teikyo University of Science, Tokyo 120-0045, Japan
| | - Harumi Katsumata
- Institute for Advanced Medical Sciences, Nippon Medical School, Kanagawa 211-8533, Japan
| | - Misao Terada
- Laboratory Animal Research Center, Dokkyo Medical University, Tochigi 321-0293, Japan
| | - Toshio Akimoto
- Division of Laboratory Animal Science, Nippon Medical School, Tokyo 113-8602, Japan
| | - Yasuo Sakuma
- University of Tokyo Health Science, Tokyo 206-0033, Japan
| | - Shiro Minami
- Institute for Advanced Medical Sciences, Nippon Medical School, Kanagawa 211-8533, Japan
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18
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Bester-Meredith JK, Burns JN, Conley MF, Mammarella GE, Ng ND. Peromyscus as a model system for understanding the regulation of maternal behavior. Semin Cell Dev Biol 2016; 61:99-106. [PMID: 27381343 DOI: 10.1016/j.semcdb.2016.07.001] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2016] [Revised: 06/30/2016] [Accepted: 07/01/2016] [Indexed: 12/31/2022]
Abstract
The genus Peromyscus has been used as a model system for understanding maternal behavior because of the diversity of reproductive strategies within this genus. This review will describe the ecological factors that determine litter size and litter quality in polygynous species such as Peromyscus leucopus and Peromyscus maniculatus. We will also outline the physiological and social factors regulating maternal care in Peromyscus californicus, a monogamous and biparental species. Because biparental care is relatively rare in mammals, most research in P. californicus has focused on understanding the biology of paternal care while less research has focused on understanding maternal care. As a result, the social, sensory, and hormonal cues used to coordinate parental care between male and female P. californicus have been relatively well-studied. However, less is known about the physiology of maternal care in P. californicus and in other Peromyscus species. The diversity of the genus Peromyscus provides the potential for future research to continue to examine how variation in social systems has shaped the mechanisms that underlie maternal care.
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Affiliation(s)
- Janet K Bester-Meredith
- Seattle Pacific University, Department of Biology, 3307 3rd Ave West, Seattle, WA 98119, USA.
| | - Jennifer N Burns
- Seattle Pacific University, Department of Biology, 3307 3rd Ave West, Seattle, WA 98119, USA
| | - Mariah F Conley
- Seattle Pacific University, Department of Biology, 3307 3rd Ave West, Seattle, WA 98119, USA
| | - Grace E Mammarella
- Seattle Pacific University, Department of Biology, 3307 3rd Ave West, Seattle, WA 98119, USA
| | - Nathaniel D Ng
- Seattle Pacific University, Department of Biology, 3307 3rd Ave West, Seattle, WA 98119, USA
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19
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Harris BN, Carr JA. The role of the hypothalamus-pituitary-adrenal/interrenal axis in mediating predator-avoidance trade-offs. Gen Comp Endocrinol 2016; 230-231:110-42. [PMID: 27080550 DOI: 10.1016/j.ygcen.2016.04.006] [Citation(s) in RCA: 51] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/11/2015] [Revised: 04/07/2016] [Accepted: 04/09/2016] [Indexed: 11/20/2022]
Abstract
Maintaining energy balance and reproducing are important for fitness, yet animals have evolved mechanisms by which the hypothalamus-pituitary-adrenal/interrenal (HPA/HPI) axis can shut these activities off. While HPA/HPI axis inhibition of feeding and reproduction may have evolved as a predator defense, to date there has been no review across taxa of the causal evidence for such a relationship. Here we review the literature on this topic by addressing evidence for three predictions: that exposure to predators decreases reproduction and feeding, that exposure to predators activates the HPA/HPI axis, and that predator-induced activation of the HPA/HPI axis inhibits foraging and reproduction. Weight of evidence indicates that exposure to predator cues inhibits several aspects of foraging and reproduction. While the evidence from fish and mammals supports the hypothesis that predator cues activate the HPA/HPI axis, the existing data in other vertebrate taxa are equivocal. A causal role for the HPA axis in predator-induced suppression of feeding and reproduction has not been demonstrated to date, although many studies report correlative relationships between HPA activity and reproduction and/or feeding. Manipulation of HPA/HPI axis signaling will be required in future studies to demonstrate direct mediation of predator-induced inhibition of feeding and reproduction. Understanding the circuitry linking sensory pathways to their control of the HPA/HPI axis also is needed. Finally, the role that fear and anxiety pathways play in the response of the HPA axis to predator cues is needed to better understand the role that predators have played in shaping anxiety related behaviors in all species, including humans.
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Affiliation(s)
- Breanna N Harris
- Department of Biological Sciences, Texas Tech University, Lubbock, TX 79409, United States
| | - James A Carr
- Department of Biological Sciences, Texas Tech University, Lubbock, TX 79409, United States.
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20
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Leuner B, Sabihi S. The birth of new neurons in the maternal brain: Hormonal regulation and functional implications. Front Neuroendocrinol 2016; 41:99-113. [PMID: 26969795 PMCID: PMC4942360 DOI: 10.1016/j.yfrne.2016.02.004] [Citation(s) in RCA: 59] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/05/2015] [Revised: 02/25/2016] [Accepted: 02/27/2016] [Indexed: 12/21/2022]
Abstract
The maternal brain is remarkably plastic and exhibits multifaceted neural modifications. Neurogenesis has emerged as one of the mechanisms by which the maternal brain exhibits plasticity. This review highlights what is currently known about peripartum-associated changes in adult neurogenesis and the underlying hormonal mechanisms. We also consider the functional consequences of neurogenesis in the peripartum brain and extent to which this process may play a role in maternal care, cognitive function and postpartum mood. Finally, while most work investigating the effects of parenting on adult neurogenesis has focused on mothers, a few studies have examined fathers and these results are also discussed.
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Affiliation(s)
- Benedetta Leuner
- The Ohio State University, Department of Psychology, Columbus, OH, USA; The Ohio State University, Department of Neuroscience, Columbus, OH, USA; The Ohio State University, Behavioral Neuroendocrinology Group, Columbus, OH, USA.
| | - Sara Sabihi
- The Ohio State University, Department of Psychology, Columbus, OH, USA
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21
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Andrew JR, Saltzman W, Chappell MA, Garland T. Consequences of Fatherhood in the Biparental California Mouse (Peromyscus californicus): Locomotor Performance, Metabolic Rate, and Organ Masses. Physiol Biochem Zool 2016; 89:130-40. [PMID: 27082723 DOI: 10.1086/685435] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Although effects of motherhood on mothers have been well documented in mammals, the effects of fatherhood on fathers are not well known. We evaluated effects of being a father on key metabolic and performance measures in the California mouse, Peromyscus californicus. California mice are genetically monogamous in the wild, and fathers show similar parental behavior to mothers, with the exception of lactation. To investigate the impact of fatherhood on fathers, focal males were paired with an intact female (breeding males), a tubally ligated female (nonbreeding males), or another male (virgins). Starting 3-5 d after the birth of each breeding pair's first litter, males were tested for locomotor performance (maximum sprint speed, treadmill endurance), basal metabolic rate (BMR), and maximum oxygen consumption ([Formula: see text]). At the end of the 11-d test period, mice were euthanized, hematocrit was determined, and organs were weighed. Speed, endurance, and [Formula: see text] were significantly repeatable between two replicate measurement days but did not differ among groups, nor did BMR. Breeding males had significantly larger hind limb muscles than did nonbreeding males, whereas virgin males had heavier subcutaneous fat pads than did nonbreeding and breeding males. Several correlations were observed at the level of individual variation (residuals from ANCOVA models), including positive correlations for endurance with [Formula: see text], [Formula: see text] with testes mass, and some of the digestion-related organs with each other. These results indicate that fatherhood may not have pronounced performance, metabolic, or morphological effects on fathers, at least under standard laboratory conditions and across a single breeding cycle.
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22
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Bales KL, Saltzman W. Fathering in rodents: Neurobiological substrates and consequences for offspring. Horm Behav 2016; 77:249-59. [PMID: 26122293 PMCID: PMC4691427 DOI: 10.1016/j.yhbeh.2015.05.021] [Citation(s) in RCA: 100] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/24/2015] [Revised: 05/27/2015] [Accepted: 05/28/2015] [Indexed: 01/08/2023]
Abstract
This article is part of a Special Issue "Parental Care". Paternal care, though rare among mammals, is routinely displayed by several species of rodents. Here we review the neuroanatomical and hormonal bases of paternal behavior, as well as the behavioral and neuroendocrine consequences of paternal behavior for offspring. Fathering behavior is subserved by many of the same neural substrates which are also involved in maternal behavior (for example, the medial preoptic area of the hypothalamus). While gonadal hormones such as testosterone, estrogen, and progesterone, as well as hypothalamic neuropeptides such as oxytocin and vasopressin, and the pituitary hormone prolactin, are implicated in the activation of paternal behavior, there are significant gaps in our knowledge of their actions, as well as pronounced differences between species. Removal of the father in biparental species has long-lasting effects on behavior, as well as on these same neuroendocrine systems, in offspring. Finally, individual differences in paternal behavior can have similarly long-lasting, if more subtle, effects on offspring behavior. Future studies should examine similar outcome measures in multiple species, including both biparental species and closely related uniparental species. Careful phylogenetic analyses of the neuroendocrine systems presumably important to male parenting, as well as their patterns of gene expression, will also be important in establishing the next generation of hypotheses regarding the regulation of male parenting behavior.
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Affiliation(s)
- Karen L Bales
- Department of Psychology, University of California, Davis, USA; California National Primate Research Center, USA.
| | - Wendy Saltzman
- Department of Biology, University of California, Riverside, USA
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23
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Orikasa C, Nagaoka K, Katsumata H, Sato M, Kondo Y, Minami S, Sakuma Y. Social isolation prompts maternal behavior in sexually naïve male ddN mice. Physiol Behav 2015; 151:9-15. [PMID: 26166155 DOI: 10.1016/j.physbeh.2015.07.007] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2015] [Revised: 07/02/2015] [Accepted: 07/03/2015] [Indexed: 10/23/2022]
Abstract
Maternal behavior in mice is considered to be sexually dimorphic; that is, females show maternal care for their offspring, whereas this behavior is rarely shown in males. Here, we examined how social isolation affects the interaction of adult male mice with pups. Three weeks of isolation during puberty (5-8 weeks old) induced retrieving and crouching when exposed to pups, while males with 1 week isolation (7-8 weeks old) also showed such maternal care, but were less responsive to pups. We also examined the effect of isolation during young adulthood (8-11 weeks old), and found an induction of maternal behavior comparable to that in younger male mice. This effect was blocked by exposure to chemosensory and auditory social signals derived from males in an attached compartment separated by doubled opaque barriers. These results demonstrate that social isolation in both puberty and postpuberty facilitates male maternal behavior in sexually naïve mice. The results also indicate that air-borne chemicals and/or sounds of male conspecifics, including ultrasonic vocalization and noise by their movement may be sufficient to interfere with the isolation effect on induction of maternal behavior in male mice.
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Affiliation(s)
- Chitose Orikasa
- Institute for Advanced Medical Science, Nippon Medical School, Kanagawa 211-8533, Japan.
| | - Kentaro Nagaoka
- Department of Veterinary Medicine, Tokyo University of Agriculture and Technology, Tokyo 183-0054, Japan
| | - Harumi Katsumata
- Institute for Advanced Medical Science, Nippon Medical School, Kanagawa 211-8533, Japan
| | - Manami Sato
- Department of Animal Sciences, Teikyo University of Science, Tokyo 120-0045, Japan
| | - Yasuhiko Kondo
- Department of Animal Sciences, Teikyo University of Science, Tokyo 120-0045, Japan
| | - Shiro Minami
- Institute for Advanced Medical Science, Nippon Medical School, Kanagawa 211-8533, Japan
| | - Yasuo Sakuma
- University of Tokyo Health Science, Tokyo 206-0033, Japan
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24
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Saltzman W, Ziegler TE. Functional significance of hormonal changes in mammalian fathers. J Neuroendocrinol 2014; 26:685-96. [PMID: 25039657 PMCID: PMC4995091 DOI: 10.1111/jne.12176] [Citation(s) in RCA: 87] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/15/2014] [Revised: 07/09/2014] [Accepted: 07/10/2014] [Indexed: 12/25/2022]
Abstract
In the 5-10% of mammals in which both parents routinely provide infant care, fathers as well as mothers undergo systematic endocrine changes as they transition into parenthood. Although fatherhood-associated changes in such hormones and neuropeptides as prolactin, testosterone, glucocorticoids, vasopressin and oxytocin have been characterised in only a small number of biparental rodents and primates, they appear to be more variable than corresponding changes in mothers, and experimental studies typically have not provided strong or consistent evidence that these endocrine shifts play causal roles in the activation of paternal care. Consequently, their functional significance remains unclear. We propose that endocrine changes in mammalian fathers may enable males to meet the species-specific demands of fatherhood by influencing diverse aspects of their behaviour and physiology, similar to many effects of hormones and neuropeptides in mothers. We review the evidence for such effects, focusing on recent studies investigating whether mammalian fathers in biparental species undergo systematic changes in (i) energetics and body composition; (ii) neural plasticity, cognition and sensory physiology; and (iii) stress responsiveness and emotionality, all of which may be mediated by endocrine changes. The few published studies, based on a small number of rodent and primate species, suggest that hormonal and neuropeptide alterations in mammalian fathers might mediate shifts in paternal energy balance, body composition and neural plasticity, although they do not appear to have major effects on stress responsiveness or emotionality. Further research is needed on a wider variety of biparental mammals, under more naturalistic conditions, to more fully determine the functional significance of hormone and neuropeptide profiles of mammalian fatherhood and to clarify how fatherhood may trade off with (or perhaps enhance) aspects of organismal function in biparental mammals.
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Affiliation(s)
- Wendy Saltzman
- Department of Biology, University of California, Riverside
| | - Toni E. Ziegler
- Wisconsin National Primate Research Center, University of Wisconsin – Madison
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25
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Hegab IM, Shang G, Ye M, Jin Y, Wang A, Yin B, Yang S, Wei W. Defensive responses of Brandt's voles (Lasiopodomys brandtii) to chronic predatory stress. Physiol Behav 2014; 126:1-7. [DOI: 10.1016/j.physbeh.2013.12.001] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2013] [Accepted: 12/04/2013] [Indexed: 10/25/2022]
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26
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Defensive responses of Brandt's voles (Lasiopodomys brandtii) to stored cat feces. Physiol Behav 2014; 123:193-9. [DOI: 10.1016/j.physbeh.2013.10.030] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2013] [Revised: 10/04/2013] [Accepted: 10/22/2013] [Indexed: 11/19/2022]
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27
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Hegab IM, Wang A, Yin B, Yang S, Wanhong W. Behavioral and neuroendocrine response of Brandt's voles, Lasiopodomys brandtii, to odors of different species. EUR J WILDLIFE RES 2013. [DOI: 10.1007/s10344-013-0790-z] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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28
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Harris BN, de Jong TR, Yang V, Saltzman W. Chronic variable stress in fathers alters paternal and social behavior but not pup development in the biparental California mouse (Peromyscus californicus). Horm Behav 2013; 64:799-811. [PMID: 24157379 PMCID: PMC3894746 DOI: 10.1016/j.yhbeh.2013.10.007] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/21/2013] [Revised: 10/09/2013] [Accepted: 10/11/2013] [Indexed: 02/02/2023]
Abstract
Stress and chronically elevated glucocorticoid levels have been shown to disrupt parental behavior in mothers; however, almost no studies have investigated corresponding effects in fathers. The present experiment tested the hypothesis that chronic variable stress inhibits paternal behavior and consequently alters pup development in the monogamous, biparental California mouse (Peromyscus californicus). First-time fathers were assigned to one of three experimental groups: chronic variable stress (CVS, n=8), separation control (SC, n=7), or unmanipulated control (UC, n=8). The CVS paradigm (3 stressors per day for 7 days) successfully stressed mice, as evidenced by increased baseline plasma corticosterone concentrations, increased adrenal mass, decreased thymus mass, and a decrease in body mass over time. CVS altered paternal and social behavior of fathers, but major differences were observed only on day 6 of the 7-day paradigm. At that time point, CVS fathers spent less time with their pairmate and pups, and more time autogrooming, as compared to UC fathers; SC fathers spent more time behaving paternally and grooming the female mate than CVS and UC fathers. Thus, CVS blocked the separation-induced increase in social behaviors observed in the SC fathers. Nonetheless, chronic stress in fathers did not appear to alter survival or development of their offspring: pups from the three experimental conditions did not differ in body mass gain over time, in the day of eye opening, or in basal or post-stress corticosterone levels. These results demonstrate that chronic stress can transiently disrupt paternal and social behavior in P. californicus fathers, but does not alter pup development or survival under controlled, non-challenging laboratory conditions.
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Affiliation(s)
- Breanna N Harris
- Department of Biology, University of California, Riverside, CA 92521, USA; Department of Biological Sciences, Texas Tech University, Lubbock, TX 79409, USA.
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Perea-Rodriguez JP, Saltzman W. Differences in placentophagia in relation to reproductive status in the California mouse (Peromyscus californicus). Dev Psychobiol 2013; 56:812-20. [PMID: 24114333 DOI: 10.1002/dev.21154] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2012] [Accepted: 06/25/2013] [Indexed: 11/08/2022]
Abstract
Parturient females ingest placenta in most mammalian species, whereas fathers may do so in species in which both parents provide care for their offspring. To determine if the propensity to eat placenta varies with reproductive status in the biparental California mouse, we presented placenta to virgin (housed with a same-sex pairmate), expectant (pregnant with their first litter), and multiparous adult males and females. Liver was presented identically, 3-7 days later, as a control. Multiparous females were more likely to eat placenta than expectant and virgin females (p-values <0.016), whereas both multiparous and expectant males had higher incidences of placentophagia than virgins (p-values <0.016). Liver consumption did not differ among groups within either sex. These results suggest that propensity to eat placenta increases with maternal/birthing experience in females, and with paternal experience and/or cohabitation with a pregnant female in males.
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Affiliation(s)
- Juan P Perea-Rodriguez
- Department of Biology, University of California, Riverside, 3386 Spieth Hall, Riverside, CA, 92521
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De Jong TR, Harris BN, Perea-Rodriguez JP, Saltzman W. Physiological and neuroendocrine responses to chronic variable stress in male California mice (Peromyscus californicus): Influence of social environment and paternal state. Psychoneuroendocrinology 2013; 38:2023-33. [PMID: 23582312 PMCID: PMC3821767 DOI: 10.1016/j.psyneuen.2013.03.006] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/09/2013] [Revised: 02/20/2013] [Accepted: 03/18/2013] [Indexed: 11/26/2022]
Abstract
Social environment and parental state affect stress responses in mammals, but their impact may depend on the social and reproductive strategy of the species. The influences of cohabitation with a male or female conspecific, and the birth of offspring, on the physiological and endocrine responses to chronic variable stress were studied in the monogamous and biparental California mouse (Peromyscus californicus). Adult male California mice were housed either with a male cage mate (virgin males, VM), a female cage mate (pair-bonded males, PBM), or a female cage mate and their first newborn litter (new fathers, NF). VM, PBM and NF underwent a 7-day chronic variable stress paradigm (CVS, three stressors per day at semi-random times, n=7-8 per housing condition). Compared to control males (CON, n=6-7 per housing condition), CVS caused loss of body mass, increased basal plasma corticosterone concentrations, and increased basal expression of arginine vasopressin (AVP) mRNA in the paraventricular nucleus of the hypothalamus (PVN). These effects were independent of housing condition. Neither CVS nor housing condition altered novel-stressor-induced corticosterone release, spleen or testis mass, or basal expression of corticotropin-releasing hormone (CRH) mRNA in the PVN. Although CVS appeared to increase adrenal mass and reduce thymus mass specifically in NF, these effects were explained by the lower adrenal mass and higher thymus mass of NF compared to PBM and VM under control conditions. These results suggest that neither engaging in a pair bond nor becoming a father attenuates typical responses to CVS, but that fatherhood may provide a buffer against transient mild stressors (i.e., weighing and blood sampling in the control groups) in this monogamous and biparental rodent.
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Affiliation(s)
- TR De Jong
- Department of Biology, University of California, Riverside,Department of Behavioral and Molecular Neurobiology, University of
Regensburg, Regensburg, Germany
| | - BN Harris
- Department of Biology, University of California, Riverside,Evolution, Ecology, and Organismal Biology Graduate Program,
University of California, Riverside
| | - JP Perea-Rodriguez
- Department of Biology, University of California, Riverside,Evolution, Ecology, and Organismal Biology Graduate Program,
University of California, Riverside
| | - W Saltzman
- Department of Biology, University of California, Riverside,Evolution, Ecology, and Organismal Biology Graduate Program,
University of California, Riverside
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31
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Campi KL, Jameson CE, Trainor BC. Sexual Dimorphism in the Brain of the Monogamous California Mouse (Peromyscus californicus). BRAIN, BEHAVIOR AND EVOLUTION 2013; 81:236-49. [PMID: 23881046 PMCID: PMC3915401 DOI: 10.1159/000353260] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/07/2012] [Accepted: 01/04/2013] [Indexed: 11/19/2022]
Abstract
Sex differences in behavior and morphology are usually assumed to be stronger in polygynous species compared to monogamous species. A few brain structures have been identified as sexually dimorphic in polygynous rodent species, but it is less clear whether these differences persist in monogamous species. California mice are among the 5% or less of mammals that are considered to be monogamous and as such provide an ideal model to examine sexual dimorphism in neuroanatomy. In the present study we compared the volume of hypothalamic- and limbic-associated regions in female and male California mice for sexual dimorphism. We also used tyrosine hydroxylase (TH) immunohistochemistry to compare the number of dopamine neurons in the ventral tegmental area (VTA) in female and male California mice. Additionally, tract tracing was used to accurately delineate the boundaries of the VTA. The total volume of the sexually dimorphic nucleus of the preoptic area (SDN-POA), the principal nucleus of the bed nucleus of the stria terminalis (BNST), and the posterodorsal medial amygdala (MEA) was larger in males compared to females. In the SDN-POA we found that the magnitude of sex differences in the California mouse were intermediate between the large differences observed in promiscuous meadow voles and rats and the absence of significant differences in monogamous prairie voles. However, the magnitude of sex differences in MEA and the BNST were comparable to polygynous species. No sex differences were observed in the volume of the whole brain, the VTA, the nucleus accumbens or the number of TH-ir neurons in the VTA. These data show that despite a monogamous social organization, sexual dimorphisms that have been reported in polygynous rodents extend to California mice. Our data suggest that sex differences in brain structures such as the SDN-POA persist across species with different social organizations and may be an evolutionarily conserved characteristic of mammalian brains.
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Affiliation(s)
- Katharine L Campi
- Department of Psychology and Center for Neuroscience, University of California Davis, Davis, CA 95616, USA.
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Harris BN, Saltzman W. Effects of aging on hypothalamic-pituitary-adrenal (HPA) axis activity and reactivity in virgin male and female California mice (Peromyscus californicus). Gen Comp Endocrinol 2013; 186:41-9. [PMID: 23458287 PMCID: PMC3640751 DOI: 10.1016/j.ygcen.2013.02.010] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/24/2012] [Revised: 01/21/2013] [Accepted: 02/14/2013] [Indexed: 11/22/2022]
Abstract
Life history theory posits that organisms face a trade-off between current and future reproductive attempts. The physiological mechanisms mediating such trade-offs are still largely unknown, but glucocorticoid hormones are likely candidates as elevated, post-stress glucocorticoid levels have been shown to suppress both reproductive physiology and reproductive behavior. Aged individuals have a decreasing window in which to reproduce, and are thus predicted to invest more heavily in current as opposed to future reproduction. Therefore, if glucocorticoids are important in mediating the trade-off between current and future reproduction, aged animals are expected to show decreased hypothalamic-pituitary-adrenal (HPA) axis responses to stressors and to stimulation by corticotropin-releasing hormone (CRH), and enhanced responses to glucocorticoid negative feedback, as compared to younger animals. We tested this hypothesis in the monogamous, biparental California mouse by comparing baseline and post-stress corticosterone levels, as well as corticosterone responses to dexamethasone (DEX) and CRH injections, between old (∼18-20months) and young (∼4months) virgin adults of both sexes. We also measured gonadal and uterine masses as a proxy for investment in potential current reproductive effort. Adrenal glands were weighed to determine if older animal had decreased adrenal mass. Old male mice had lower plasma corticosterone levels 8h after DEX injection than did young male mice, suggesting that the anterior pituitary of older males is more sensitive to DEX-induced negative feedback. Old female mice had higher body-mass-corrected uterine mass than did young females. No other differences in corticosterone levels or organ masses were found between age groups within either sex. In conclusion, we did not find strong evidence for age-related change in HPA activity or reactivity in virgin adult male or female California mice; however, future studies investigating HPA activity and reproductive outcomes in young and old breeding adults would be illuminating.
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Affiliation(s)
- Breanna N Harris
- Department of Biology, University of California, Riverside, CA 92521, USA.
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33
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Harris BN, Saltzman W. Effect of reproductive status on hypothalamic-pituitary-adrenal (HPA) activity and reactivity in male California mice (Peromyscus californicus). Physiol Behav 2013; 112-113:70-6. [PMID: 23474132 PMCID: PMC3622192 DOI: 10.1016/j.physbeh.2013.02.016] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2012] [Accepted: 02/25/2013] [Indexed: 12/29/2022]
Abstract
Previous studies indicate that reproductive condition can alter stress response and glucocorticoid release. Although the functional significance of hypothalamic-pituitary-adrenal (HPA) axis modulation by breeding condition is not fully understood, one possible explanation is the behavior hypothesis, which states that an animal's need to express parental behavior may be driving modulation of the HPA axis. This possibility is consistent with findings of blunted activity and reactivity of the HPA axis in lactating female mammals; however, effects of reproductive status on HPA function have not been well characterized in male mammals that express parental behavior. Therefore, we tested this hypothesis in the monogamous and biparental California mouse. Several aspects of HPA activity were compared in males from three reproductive conditions: virgin males (housed with another male), non-breeding males (housed with a tubally ligated female), and first-time fathers (housed with a female and their first litter of pups). In light of the behavior hypothesis we predicted that new fathers would differ from virgin and non-breeding males in several aspects of HPA function and corticosterone (CORT) output: decreased amplitude of the diurnal rhythm in CORT, a blunted CORT increase following predator-odor stress, increased sensitivity to glucocorticoid negative feedback, and/or a blunted CORT response to pharmacological stimulation. In addition, we predicted that first-time fathers would be more resistant to CORT-induced suppression of testosterone secretion, as testosterone is important for paternal behavior in this species. We found that virgin males, non-breeding males and first-time fathers did not display any CORT differences in diurnal rhythm, response to a predator-odor stressor, or response to pharmacological suppression or stimulation. Additionally, there were no differences in circulating testosterone concentrations. Adrenal mass was, however, significantly lower in new fathers than in virgin or non-breeding males. These results suggest that the behavior hypothesis does not explain HPA function across reproductive conditions in male California mice.
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Affiliation(s)
- Breanna N Harris
- Department of Biology, University of California, Riverside, CA 92521, USA.
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34
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Harris BN, Saltzman W, de Jong TR, Milnes MR. Hypothalamic-pituitary-adrenal (HPA) axis function in the California mouse (Peromyscus californicus): Changes in baseline activity, reactivity, and fecal excretion of glucocorticoids across the diurnal cycle. Gen Comp Endocrinol 2012; 179:436-50. [PMID: 23026495 PMCID: PMC3513568 DOI: 10.1016/j.ygcen.2012.08.026] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/06/2012] [Revised: 07/07/2012] [Accepted: 08/13/2012] [Indexed: 11/18/2022]
Abstract
The California mouse, Peromyscus californicus, is an increasingly popular animal model in behavioral, neural, and endocrine studies, but little is known about its baseline hypothalamic-pituitary-adrenal (HPA) axis activity or HPA responses to stressors. We characterized plasma corticosterone (CORT) concentrations in P. californicus under baseline conditions across the diurnal cycle, in response to pharmacological manipulation of the HPA axis, and in response to a variety of stressors at different times of day. In addition, we explored the use of fecal samples to monitor adrenocortical activity non-invasively. California mice have very high baseline levels of circulating CORT that change markedly over 24h, but that do not differ between the sexes. This species may be somewhat glucocorticoid-resistant in comparison to other rodents as a relatively high dose of dexamethasone (5mg/kg, s.c.) was required to suppress plasma CORT for 8h post-injection. CORT responses to stressors and ACTH injection differed with time of day, as CORT concentrations were elevated more readily during the morning (inactive period) than in the evening (active period) when compared to time-matched control. Data from (3)H-CORT injection studies show that the time course for excretion of fecal CORT, or glucocorticoid metabolites, differs with time of injection. Mice injected in the evening excreted the majority of fecal radioactivity 2-4h post-injection whereas mice injected during the morning did so at 14-16h post-injection. Unfortunately, the antibody we used does not adequately bind the most prevalent fecal glucocorticoid metabolites and therefore we could not validate its use for fecal assays.
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Affiliation(s)
- Breanna N Harris
- Department of Biology, University of California, Riverside, CA 92521, USA.
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35
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de Jong TR, Korosi A, Harris BN, Perea-Rodriguez JP, Saltzman W. Individual Variation in Paternal Responses of Virgin Male California Mice (Peromyscus californicus): Behavioral and Physiological Correlates. Physiol Biochem Zool 2012; 85:740-51. [DOI: 10.1086/665831] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
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36
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Dlugosz EM, Harris BN, Saltzman W, Chappell MA. Glucocorticoids, aerobic physiology, and locomotor behavior in California mice. Physiol Biochem Zool 2012; 85:671-83. [PMID: 23099464 DOI: 10.1086/667809] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
The glucocorticoid hormones corticosterone (CORT) and cortisol influence numerous physiological, morphological, and behavioral functions. However, few studies have addressed possible relationships between individual differences in glucocorticoid concentrations and whole-animal performance or metabolism. Because CORT is important in glucose regulation and energy metabolism and can influence activity levels, we hypothesized that individual variation in baseline circulating CORT levels would correlate with individual differences in energy expenditure (routine and maximal), aerobic physiology, voluntary exercise on wheels, and organ masses. We tested this hypothesis in the California mouse (Peromyscus californicus). We collected data from 54 adult, colony-bred mice on baseline CORT levels (measured near both the circadian peak and the circadian trough), voluntary wheel running and its energetic costs, maximal oxygen consumption during forced treadmill exercise ([Formula: see text]), basal metabolic rate, and relative organ masses. We found surprisingly few statistically significant relationships among CORT, energy metabolism, behavior, and organ masses, and these relationships appeared to differ between males and females. These findings suggest that individual differences in baseline CORT levels are not an important determinant of voluntary activity levels or aerobic performance in California mice.
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Affiliation(s)
- Elizabeth M Dlugosz
- Department of Biology and Graduate Program in Evolution, Ecology, and Organismal Biology, University of California, Riverside, California 92521, USA.
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37
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Chauke M, de Jong TR, Garland T, Saltzman W. Paternal responsiveness is associated with, but not mediated by reduced neophobia in male California mice (Peromyscus californicus). Physiol Behav 2012; 107:65-75. [PMID: 22634280 DOI: 10.1016/j.physbeh.2012.05.012] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2011] [Revised: 04/21/2012] [Accepted: 05/14/2012] [Indexed: 01/21/2023]
Abstract
Hormones associated with pregnancy and parturition have been implicated in facilitating the onset of maternal behavior via reductions in neophobia, anxiety, and stress responsiveness. To determine whether the onset of paternal behavior has similar associations in biparental male California mice (Peromyscus californicus), we compared paternal responsiveness, neophobia (novel-object test), and anxiety-like behavior (elevated plus maze, EPM) in isolated virgins (housed alone), paired virgins (housed with another male), expectant fathers (housed with pregnant pairmate), and new fathers (housed with pairmate and pups). Corticotropin-releasing hormone (CRH) and Fos immunoreactivity (IR) were quantified in brain tissues following exposure to a predator-odor stressor or under baseline conditions. New fathers showed lower anxiety-like behavior than expectant fathers and isolated virgins in EPM tests. In all housing conditions, stress elevated Fos-IR in the hypothalamic paraventricular nucleus (PVN). Social isolation reduced overall (baseline and stress-induced) Fos- and colocalized Fos/CRH-IR, and increased overall CRH-IR, in the PVN. In the central nucleus of the amygdala, social isolation increased stress-induced CRH-IR and decreased stress-induced activation of CRH neurons. Across all housing conditions, paternally behaving males displayed more anxiety-related behavior than nonpaternal males in the EPM, but showed no differences in CRH- or Fos-IR. Finally, the latency to engage in paternal behavior was positively correlated with the latency to approach a novel object. These results suggest that being a new father does not reduce anxiety, neophobia, or neural stress responsiveness. Low levels of neophobia, however, were associated with, but not necessary for paternal responsiveness.
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Affiliation(s)
- Miyetani Chauke
- Neuroscience Graduate Program, University of California, Riverside, CA 92521, USA.
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38
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Smith AS, Wang Z. Salubrious effects of oxytocin on social stress-induced deficits. Horm Behav 2012; 61:320-30. [PMID: 22178036 PMCID: PMC3350103 DOI: 10.1016/j.yhbeh.2011.11.010] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/20/2011] [Revised: 11/19/2011] [Accepted: 11/21/2011] [Indexed: 12/29/2022]
Abstract
Social relationships are a fundamental aspect of life, affecting social, psychological, physiological, and behavioral functions. While positive social interactions can attenuate stress and promote health, the social environment can also be a major source of stress when it includes social disruption, confrontation, isolation, or neglect. Social stress can impair the basal function and stress-induced activation of the hypothalamic-pituitary-adrenal (HPA) axis, impairing function of multiple biological systems and posing a risk to mental and physical health. In contrast, social support can ameliorate stress-induced physiological and immunological deficits, reducing the risk of subsequent psychological distress and improving an individual's overall well-being. For better clinical treatment of these physiological and mental pathologies, it is necessary to understand the regulatory mechanisms of stress-induced pathologies as well as determine the underlying biological mechanisms that regulate social buffering of the stress system. A number of ethologically relevant animal models of social stress and species that form strong adult social bonds have been utilized to study the etiology, treatment, and prevention of stress-related disorders. While undoubtedly a number of biological pathways contribute to the social buffering of the stress response, the convergence of evidence denotes the regulatory effects of oxytocin in facilitating social bond-promoting behaviors and their effect on the stress response. Thus, oxytocin may be perceived as a common regulatory element of the social environment, stress response, and stress-induced risks on mental and physical health. This article is part of a Special Issue entitled Oxytocin, Vasopressin, and Social Behavior.
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Affiliation(s)
- Adam S Smith
- Department of Psychology and Program in Neuroscience, Florida State University, Tallahassee, FL 32306-1270, USA.
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39
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Harris BN, Perea-Rodriguez JP, Saltzman W. Acute effects of corticosterone injection on paternal behavior in California mouse (Peromyscus californicus) fathers. Horm Behav 2011; 60:666-75. [PMID: 21939660 DOI: 10.1016/j.yhbeh.2011.09.001] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/01/2011] [Revised: 09/03/2011] [Accepted: 09/06/2011] [Indexed: 10/17/2022]
Abstract
Glucocorticoids are thought to mediate the disruption of parental behavior in response to acute and chronic stress. Previous research supports their role in chronic stress; however, no study has experimentally tested the effects of acute glucocorticoid elevation on paternal behavior. We tested the prediction that acute corticosterone (CORT) increases would decrease paternal behavior in California mouse fathers and would lead to longer-term effects on reproductive success, as even short-term increases in CORT have been shown to produce lasting effects on the hypothalamic-pituitary-adrenal axis. First-time fathers were injected with 30 mg/kg CORT, 60 mg/kg CORT or vehicle, or left unmanipulated. Interactions between the male and its pup(s) were recorded 1.5-2h after injection and scored for paternal and non-paternal behavior. Treatment groups were combined into control (unmanipulated + vehicle, n = 15) and CORT (30 mg/kg + 60 mg/kg, n = 16) for analysis based on resulting plasma CORT concentrations. CORT treatment did not alter paternal or non-paternal behaviors or any long-term measures (male body mass or temperature, pup growth rate, pup survival, interbirth interval, number or mass of pups born in the second litter). Fathers showed a significant rise in body mass at day 30 postpartum, followed by a decrease in body mass after the birth of the second litter; however, this pattern did not differ between the CORT and control groups. In summary, acute elevation of plasma CORT did not alter direct paternal behavior, body mass, or reproductive outcomes, suggesting that acute CORT elevation alone does not overtly disrupt paternal care in this biparental mammal.
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Affiliation(s)
- Breanna N Harris
- Department of Biology, University of California, Riverside, CA 92521, USA.
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40
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Smith AS, Birnie AK, French JA. Social isolation affects partner-directed social behavior and cortisol during pair formation in marmosets, Callithrix geoffroyi. Physiol Behav 2011; 104:955-61. [PMID: 21712050 PMCID: PMC3183141 DOI: 10.1016/j.physbeh.2011.06.014] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2011] [Revised: 06/10/2011] [Accepted: 06/14/2011] [Indexed: 10/18/2022]
Abstract
Pair-bonded relationships form during periods of close spatial proximity and high sociosexual contact. Like other monogamous species, marmosets form new social pairs after emigration or ejection from their natal group resulting in periods of social isolation. Thus, pair formation often occurs following a period of social instability and a concomitant elevation in stress physiology. Research is needed to assess the effects that prolonged social isolation has on the behavioral and cortisol response to the formation of a new social pair. We examined the sociosexual behavior and cortisol during the first 90-days of cohabitation in male and female Geoffroy's tufted-ear marmosets (Callithrix geoffroyi) paired either directly from their natal group (Natal-P) or after a prolonged period of social isolation (ISO-P). Social isolation prior to pairing seemed to influence cortisol levels, social contact, and grooming behavior; however, sexual behavior was not affected. Cortisol levels were transiently elevated in all paired marmosets compared to natal-housed marmosets. However, ISO-P marmosets had higher cortisol levels throughout the observed pairing period compared to Natal-P marmoset. This suggests that the social instability of pair formation may lead to a transient increase in hypothalamic-pituitary-adrenal (HPA) axis activity while isolation results in a prolonged HPA axis dysregulation. In addition, female social contact behavior was associated with higher cortisol levels at the onset of pairing; however, this was not observed in males. Thus, isolation-induced social contact with a new social partner may be enhanced by HPA axis activation, or a moderating factor.
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Affiliation(s)
- Adam S Smith
- Department of Psychology and Callitrichid Research Facility, University of Nebraska at Omaha, Omaha, NE, United States.
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