1
|
Lutterschmidt DI, Stratton K, Winters TJ, Martin S, Merlino LJ. Neural thyroid hormone metabolism integrates seasonal changes in environmental temperature with the neuroendocrine reproductive axis. Horm Behav 2024; 161:105517. [PMID: 38422864 DOI: 10.1016/j.yhbeh.2024.105517] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/21/2023] [Revised: 02/15/2024] [Accepted: 02/20/2024] [Indexed: 03/02/2024]
Abstract
We asked if environmental temperature alters thyroid hormone metabolism within the hypothalamus, thereby providing a neuroendocrine mechanism by which temperature could be integrated with photoperiod to regulate seasonal rhythms. We used immunohistochemistry to assess the effects of low-temperature winter dormancy at 4 °C or 12 °C on thyroid-stimulating hormone (TSH) within the infundibulum of the pituitary as well as deiodinase 2 (Dio2) and 3 (Dio3) within the hypothalamus of red-sided garter snakes (Thamnophis sirtalis). Both the duration and, in males, magnitude of low-temperature dormancy altered deiodinase immunoreactivity within the hypothalamus, increasing the area of Dio2-immunoreactivity in males and females and decreasing the number of Dio3-immunoreactive cells in males after 8-16 weeks. Reciprocal changes in Dio2/3 favor the accumulation of triiodothyronine within the hypothalamus. Whether TSH mediates these effects requires further study, as significant changes in TSH-immunoreactive cell number were not observed. Temporal changes in deiodinase immunoreactivity coincided with an increase in the proportion of males exhibiting courtship behavior as well as changes in the temporal pattern of courtship behavior after emergence. Our findings mirror those of previous studies, in which males require low-temperature exposure for at least 8 weeks before significant changes in gonadotropin-releasing hormone immunoreactivity and sex steroid hormones are observed. Collectively, these data provide evidence that the neuroendocrine pathway regulating the reproductive axis via thyroid hormone metabolism is capable of transducing temperature information. Because all vertebrates can potentially use temperature as a supplementary cue, these results are broadly applicable to understanding how environment-organism interactions mediate seasonally adaptive responses.
Collapse
Affiliation(s)
| | - Kalera Stratton
- Department of Biology, Portland State University, OR, United States
| | - Treven J Winters
- Department of Biology, Portland State University, OR, United States
| | - Stephanie Martin
- Department of Biology, Portland State University, OR, United States
| | - Lauren J Merlino
- Department of Biology, Portland State University, OR, United States
| |
Collapse
|
2
|
Yamagishi G, Miyagawa S. Neuroendocrinology of Reproduction and Social Behaviors in Reptiles: Advances Made in the Last Decade. Zoolog Sci 2024; 41:87-96. [PMID: 38587521 DOI: 10.2108/zs230060] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2023] [Accepted: 10/03/2023] [Indexed: 04/09/2024]
Abstract
Among amniotes, reptiles are ectothermic and are clearly distinguished from mammals and birds. Reptiles show great diversity not only in species numbers, but also in ecological and physiological features. Although their physiological diversity is an interesting research topic, less effort has been made compared to that for mammals and birds, in part due to lack of established experimental models and techniques. However, progress, especially in the field of neuroendocrinology, has been steadily made. With this process, basic data on selected reptilian species have been collected. This review article presents the progress made in the last decade, which includes 1) behavioral regulation by sex steroid hormones, 2) regulation of seasonal reproduction by melatonin and GnRH, and 3) regulation of social interaction by arginine vasotocin. Through these research topics, we provide insights into the physiology of reptiles and the latest findings in the field of amniote neuroendocrinology.
Collapse
Affiliation(s)
- Genki Yamagishi
- Department of Biological Science and Technology, Faculty of Advanced Engineering, Tokyo University of Science, Katsushika-ku, Tokyo 125-8585, Japan,
| | - Shinichi Miyagawa
- Department of Biological Science and Technology, Faculty of Advanced Engineering, Tokyo University of Science, Katsushika-ku, Tokyo 125-8585, Japan,
| |
Collapse
|
3
|
Winters TJ, Martin S, Anderson H, Procter ND, Lutterschmidt DI. Role of melatonin in temperature-induced activation of the neuroendocrine reproductive axis in garter snakes. BRAIN, BEHAVIOR AND EVOLUTION 2022; 97:167-183. [PMID: 35220307 DOI: 10.1159/000523788] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/09/2021] [Accepted: 02/16/2022] [Indexed: 12/18/2022]
Abstract
An animal's ability to respond optimally to changing environmental conditions is paramount to successfully reproducing and thus maximizing fitness. Studies on photoperiod-induced changes in neural thyroid hormone metabolism have conclusively linked environmental cues to the neuroendocrine reproductive axis of birds and mammals. Whether this conserved mechanism also transduces changes in environmental temperature, however, has not been fully addressed. We investigated whether the hormone melatonin mediates the effects of low temperature winter dormancy on thyroid hormone metabolism within the hypothalamus of red-sided garter snakes (Thamnophis sirtalis parietalis). To address this question, we used immunohistochemistry to assess changes in thyroid stimulating hormone (TSH) in the infundibulum of the pituitary and deiodinase 3 (Dio3) and gonadotropin-releasing hormone (GnRH) in the hypothalamus. We also asked if changes in TSH, Dio3, and/or GnRH immunoreactivity are associated with changes in male courtship behavior. In contrast to our predictions, 6 weeks of low-temperature dormancy at 4°C significantly decreased TSH-labeled cell number in the infundibulum; it is possible that an initial decrease in TSH is related to the release of snakes from temperature refractoriness. Treatment of snakes with the melatonin precursor 5-hydroxytryptophan during dormancy at 4°C both reversed the temperature-induced change in TSH-immunoreactivity and disrupted the temporal pattern of male courtship behavior. These results suggest that TSH cells within the infundibulum are both modulated by temperature and sensitive to changes in melatonin. As predicted, male snakes hibernated at an elevated temperature of 12°C for 6 weeks and treated with vehicle showed no change in TSH-, Dio3-, or GnRH-immunoreactive cell number. Treatment of snakes with the melatonin receptor antagonist luzindole was not sufficient in rescuing the effects of dormancy at 12°C on TSH immunoreactivity or courtship behavior. However, luzindole-treated snakes showed a significant increase in GnRH- immunoreactive cell number, suggesting that melatonin exerts an inhibitory effect on GnRH in garter snakes. In summary, our results provide critical insights into the mechanisms that mediate the effects of temperature on reproductive physiology and behavior.
Collapse
Affiliation(s)
- Treven J Winters
- Department of Biology, Portland State University, Portland, Oregon, USA
| | - Stephanie Martin
- Department of Biology, Portland State University, Portland, Oregon, USA
| | - Holden Anderson
- Department of Biology, Portland State University, Portland, Oregon, USA
| | - Nichole D Procter
- Department of Biology, Portland State University, Portland, Oregon, USA
| | | |
Collapse
|
4
|
Hallas JM, Parchman TL, Feldman CR. Phylogenomic analyses resolve relationships among garter snakes (Thamnophis: Natricinae: Colubridae) and elucidate biogeographic history and morphological evolution. Mol Phylogenet Evol 2021; 167:107374. [PMID: 34896619 DOI: 10.1016/j.ympev.2021.107374] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2021] [Revised: 11/02/2021] [Accepted: 11/15/2021] [Indexed: 11/19/2022]
Abstract
Garter snakes (Thamnophis) are a successful group of natricines endemic to North America. They have become important natural models for ecological and evolutionary research, yet prior efforts to resolve phylogenetic relationships have resulted in conflicting topologies and weak support for certain relationships. Here, we use genomic data generated with a reduced representation double-digest RADseq approach to reassess evolutionary relationships across Thamnophis. We then use the resulting phylogeny to better understand how biogeography and feeding ecology have influenced lineage diversification and morphological evolution. We recovered highly congruent and strongly supported topologies from maximum likelihood and Bayesian analyses, but some discordance with a multispecies coalescent approach. All phylogenomic estimates split Thamnophis into two clades largely defined by northern and southern North American species. Divergence time estimates and biogeographic analyses indicate a mid-Miocene origin of Thamnophis in Mexico. In addition, historic vicariant events thought to explain biogeographic patterns in other lineages (e.g., Isthmus of Tehuantepec, Rocky Mountain Range, and Trans-Mexican Volcanic Belt) appear to have influenced patterns of diversification in Thamnophis as well. Analyses of morphological traits associated with feeding ecology showed moderate to strong phylogenetic signal. Nevertheless, phylogenetic ANOVA suggested significant differences in certain cranial morphologies between aquatic specialists and garter snakes that are terrestrial-aquatic generalists, independent of evolutionary history. Our new estimate of Thamnophis phylogeny yields an improved understanding of the biogeographic history and morphological evolution of garter snakes, and provides a robust framework for future research on these snakes.
Collapse
Affiliation(s)
- Joshua M Hallas
- Department of Biology, University of Nevada, Reno, 1664 North Virginia Street, Reno, NV 89557-0314, USA; Graduate Program in Ecology, Evolution, and Conservation Biology, University of Nevada, Reno, 1664 North Virginia Street, Reno, NV 89557-0314, USA.
| | - Thomas L Parchman
- Department of Biology, University of Nevada, Reno, 1664 North Virginia Street, Reno, NV 89557-0314, USA; Graduate Program in Ecology, Evolution, and Conservation Biology, University of Nevada, Reno, 1664 North Virginia Street, Reno, NV 89557-0314, USA
| | - Chris R Feldman
- Department of Biology, University of Nevada, Reno, 1664 North Virginia Street, Reno, NV 89557-0314, USA; Graduate Program in Ecology, Evolution, and Conservation Biology, University of Nevada, Reno, 1664 North Virginia Street, Reno, NV 89557-0314, USA
| |
Collapse
|
5
|
Lutterschmidt DI, Lucas AR, Summers AR. Trans-seasonal activation of the neuroendocrine reproductive axis: Low-temperature winter dormancy modulates gonadotropin-releasing hormone neurons in garter snakes. JOURNAL OF EXPERIMENTAL ZOOLOGY PART 2021; 337:50-64. [PMID: 34270177 DOI: 10.1002/jez.2506] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/31/2021] [Revised: 06/20/2021] [Accepted: 06/23/2021] [Indexed: 12/22/2022]
Abstract
All animals use external cues from the environment to accurately time life-history events. How the brain decodes environmental stimuli to effect changes in physiology and behavior, however, is poorly understood, particularly with regard to supplementary environmental cues such as temperature. We asked if low-temperature dormancy alters the synthesis and/or release of gonadotropin-releasing hormone (GnRH). We used the well-studied red-sided garter snake (Thamnophis sirtalis) for this study, as low-temperature exposure is both necessary and sufficient to induce reproduction in northern populations of this species. Snakes were collected from the field and hibernated at 4°C or 10°C in complete darkness for up to 16 weeks. In males, increasing duration of low-temperature dormancy significantly increased GnRH-immunoreactive cell number and GnRH soma size (a proxy for relative cell activity) in the forebrain. These changes mirrored those in male reproductive behavior (reported previously) and plasma androgen concentrations. The changes in GnRH cell area observed in males were specific to the neuroendocrine population of cells in the medial preoptic area; soma size in the rostral GnRH cells did not change. Finally, temperature-induced changes in GnRH were sexually dimorphic: neither hibernation temperature nor the duration of winter dormancy significantly modulated GnRH cell number or soma size in females, despite the fact that plasma estradiol and corticosterone increased significantly in response to both. These data demonstrate that the neuroendocrine GnRH system is sensitive to environmental temperature and suggest that GnRH neurons play a conserved but trans-seasonal role in mediating changes in reproductive physiology and behavior in dissociated breeders.
Collapse
Affiliation(s)
| | - Ashley R Lucas
- Department of Biology, Portland State University, Portland, Oregon, USA
| | - Andrew R Summers
- Department of Biology, Portland State University, Portland, Oregon, USA
| |
Collapse
|
6
|
Hoops D, Desfilis E, Ullmann JFP, Janke AL, Stait-Gardner T, Devenyi GA, Price WS, Medina L, Whiting MJ, Keogh JS. A 3D MRI-based atlas of a lizard brain. J Comp Neurol 2018; 526:2511-2547. [PMID: 29931765 DOI: 10.1002/cne.24480] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2017] [Revised: 04/01/2018] [Accepted: 04/03/2018] [Indexed: 02/05/2023]
Abstract
Magnetic resonance imaging (MRI) is an established technique for neuroanatomical analysis, being particularly useful in the medical sciences. However, the application of MRI to evolutionary neuroscience is still in its infancy. Few magnetic resonance brain atlases exist outside the standard model organisms in neuroscience and no magnetic resonance atlas has been produced for any reptile brain. A detailed understanding of reptilian brain anatomy is necessary to elucidate the evolutionary origin of enigmatic brain structures such as the cerebral cortex. Here, we present a magnetic resonance atlas for the brain of a representative squamate reptile, the Australian tawny dragon (Agamidae: Ctenophorus decresii), which has been the subject of numerous ecological and behavioral studies. We used a high-field 11.74T magnet, a paramagnetic contrasting-enhancing agent and minimum-deformation modeling of the brains of thirteen adult male individuals. From this, we created a high-resolution three-dimensional model of a lizard brain. The 3D-MRI model can be freely downloaded and allows a better comprehension of brain areas, nuclei, and fiber tracts, facilitating comparison with other species and setting the basis for future comparative evolution imaging studies. The MRI model and atlas of a tawny dragon brain (Ctenophorus decresii) can be viewed online and downloaded using the Wiley Biolucida Server at wiley.biolucida.net.
Collapse
Affiliation(s)
- Daniel Hoops
- Division of Ecology & Evolution, Research School of Biology, The Australian National University, Canberra, ACT, Australia
| | - Ester Desfilis
- Laboratory of Evolutionary and Developmental Neurobiology, Department of Experimental Medicine, Lleida Institute for Biomedical Research Fundació Dr. Pifarré (IRBLleida), University of Lleida, Lleida, Spain
| | - Jeremy F P Ullmann
- Center for Advanced Imaging, The University of Queensland, Brisbane, QLD, Australia
| | - Andrew L Janke
- Center for Advanced Imaging, The University of Queensland, Brisbane, QLD, Australia
| | - Timothy Stait-Gardner
- Nanoscale Organization and Dynamics Group, Western Sydney University, Penrith, NSW, Australia
| | - Gabriel A Devenyi
- Douglas Hospital Research Centre, Douglas Mental Health University Institute, Montreal, Quebec, Canada.,Department of Psychiatry, McGill University, Montreal, Quebec, Canada
| | - William S Price
- Nanoscale Organization and Dynamics Group, Western Sydney University, Penrith, NSW, Australia
| | - Loreta Medina
- Laboratory of Evolutionary and Developmental Neurobiology, Department of Experimental Medicine, Lleida Institute for Biomedical Research Fundació Dr. Pifarré (IRBLleida), University of Lleida, Lleida, Spain
| | - Martin J Whiting
- Department of Biological Sciences, Macquarie University, Sydney, NSW, Australia
| | - J Scott Keogh
- Division of Ecology & Evolution, Research School of Biology, The Australian National University, Canberra, ACT, Australia
| |
Collapse
|
7
|
Ashton SE, Vernasco BJ, Moore IT, Parker MR. Sex and seasonal differences in mRNA expression of estrogen receptor α (ESR1) in red-sided garter snakes (Thamnophis sirtalis parietalis). Gen Comp Endocrinol 2018; 267:59-65. [PMID: 29807033 DOI: 10.1016/j.ygcen.2018.05.026] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/31/2017] [Revised: 04/30/2018] [Accepted: 05/24/2018] [Indexed: 11/30/2022]
Abstract
Estrogens are important regulators of reproductive physiology including sexual signal expression and vitellogenesis. For the regulation to occur, the hormone must bind and activate receptors in target tissues, and expression of the receptors can vary by sex and/or season. By simultaneously comparing circulating hormone levels with receptor expression, a more complete understanding of hormone action can be gained. Our study species, the red-sided garter snake (Thamnophis sirtalis parietalis), provides an excellent opportunity to study the interaction between sex steroid hormones and receptor expression in addition to sexual dimorphism and seasonality. During the spring mating season, male garter snakes rely exclusively on the female's skin-based, estrogen-dependent sex pheromone to direct courtship. Males can be stimulated to produce this sexual attractiveness pheromone by treatment with estradiol (E2), which also induces male vitellogenesis. Estrogen receptors (ESRs) are required to transduce the effects of estrogens, thus we used quantitative RT-PCR to analyze expression of ESR alpha (ERα; gene ESR1) mRNA in the skin and liver of wild caught male and female garter snakes across simulated spring and fall conditions in the laboratory. While ESR1 was present in the skin of both sexes, there were no sex or seasonal differences in expression levels. Liver expression of ESR1, however, was sexually dimorphic, with females showing greatest expression in fall when circulating E2 concentrations were lowest. There were no statistically significant correlations between E2 and ESR1 expression. Our data suggest that the skin of both sexes is sensitive to estrogen signaling and thus the production of sex pheromone is dependent on bioavailable levels of E2. Female expression of ESR1 in the liver may increase in the fall to prime energy storage mechanisms required for vitellogenesis the following year.
Collapse
Affiliation(s)
- Sydney E Ashton
- Department of Biology, James Madison University, Harrisonburg, VA 22807, United States; Graduate Program in Neuroscience, School of Medicine, University of Maryland, Baltimore, MD 21201, United States
| | - Ben J Vernasco
- Department of Biological Sciences, Virginia Tech, Blacksburg, VA 24061, United States
| | - Ignacio T Moore
- Department of Biological Sciences, Virginia Tech, Blacksburg, VA 24061, United States
| | - M Rockwell Parker
- Department of Biology, James Madison University, Harrisonburg, VA 22807, United States.
| |
Collapse
|
8
|
Lutterschmidt DI, Lucas AR, Karam RA, Nguyen VT, Rasmussen MR. Sexually Dimorphic Patterns of Cell Proliferation in the Brain Are Linked to Seasonal Life-History Transitions in Red-Sided Garter Snakes. Front Neurosci 2018; 12:364. [PMID: 29910707 PMCID: PMC5992280 DOI: 10.3389/fnins.2018.00364] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2017] [Accepted: 05/09/2018] [Indexed: 01/17/2023] Open
Abstract
Seasonal rhythms in physiology and behavior are widespread across diverse taxonomic groups and may be mediated by seasonal changes in neurogenesis, including cell proliferation, migration, and differentiation. We examined if cell proliferation in the brain is associated with the seasonal life-history transition from spring breeding to migration and summer foraging in a free-ranging population of red-sided garter snakes (Thamnophis sirtalis) in Manitoba, Canada. We used the thymidine analog 5-bromo-2′-deoxyuridine (BrdU) to label newly proliferated cells within the brain of adult snakes collected from the den during the mating season or from a road located along their migratory route. To assess rates of cell migration, we further categorized BrdU-labeled cells according to their location within the ventricular zone or parenchymal region of the nucleus sphericus (homolog of the amygdala), preoptic area/hypothalamus, septal nucleus, and cortex (homolog of the hippocampus). We found that cell proliferation and cell migration varied significantly with sex, the migratory status of snakes, and reproductive behavior in males. In most regions of interest, patterns of cell proliferation were sexually dimorphic, with males having significantly more BrdU-labeled cells than females prior to migration. However, during the initial stages of migration, females exhibited a significant increase in cell proliferation within the nucleus sphericus, hypothalamus, and septal nucleus, but not in any subregion of the cortex. In contrast, migrating males exhibited a significant increase in cell proliferation within the medial cortex but no other brain region. Because it is unlikely that the medial cortex plays a sexually dimorphic role in spatial memory during spring migration, we speculate that cell proliferation within the male medial cortex is associated with regulation of the hypothalamus-pituitary-adrenal axis. Finally, the only brain region where cell migration into the parenchymal region varied significantly with sex or migratory status was the hypothalamus. These results suggest that the migration of newly proliferated cells and/or the continued division of undifferentiated cells are activated earlier or to a greater extent in the hypothalamus. Our data suggest that sexually dimorphic changes in cell proliferation and cell migration in the adult brain may mediate sex differences in the timing of seasonal life-history transitions.
Collapse
Affiliation(s)
| | - Ashley R Lucas
- Department of Biology, Portland State University, Portland, OR, United States
| | - Ritta A Karam
- Department of Biology, Portland State University, Portland, OR, United States
| | - Vicky T Nguyen
- Department of Biology, Portland State University, Portland, OR, United States
| | - Meghann R Rasmussen
- Department of Biology, Portland State University, Portland, OR, United States
| |
Collapse
|
9
|
Leary CJ, Crocker‐Buta S. Rapid effects of elevated stress hormones on male courtship signals suggest a major role for the acute stress response in intra‐ and intersexual selection. Funct Ecol 2018. [DOI: 10.1111/1365-2435.13054] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
|
10
|
Manfredini F, Romero AE, Pedroso I, Paccanaro A, Sumner S, Brown MJF. Neurogenomic Signatures of Successes and Failures in Life-History Transitions in a Key Insect Pollinator. Genome Biol Evol 2017; 9:3059-3072. [PMID: 29087523 PMCID: PMC5714134 DOI: 10.1093/gbe/evx220] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/25/2017] [Indexed: 12/22/2022] Open
Abstract
Life-history transitions require major reprogramming at the behavioral and physiological level. Mating and reproductive maturation are known to trigger changes in gene transcription in reproductive tissues in a wide range of organisms, but we understand little about the molecular consequences of a failure to mate or become reproductively mature, and it is not clear to what extent these processes trigger neural as well as physiological changes. In this study, we examined the molecular processes underpinning the behavioral changes that accompany the major life-history transitions in a key pollinator, the bumblebee Bombus terrestris. We compared neuro-transcription in queens that succeeded or failed in switching from virgin and immature states, to mated and reproductively mature states. Both successes and failures were associated with distinct molecular profiles, illustrating how development during adulthood triggers distinct molecular profiles within a single caste of a eusocial insect. Failures in both mating and reproductive maturation were explained by a general up-regulation of brain gene transcription. We identified 21 genes that were highly connected in a gene coexpression network analysis: nine genes are involved in neural processes and four are regulators of gene expression. This suggests that negotiating life-history transitions involves significant neural processing and reprogramming, and not just changes in physiology. These findings provide novel insights into basic life-history transitions of an insect. Failure to mate or to become reproductively mature is an overlooked component of variation in natural systems, despite its prevalence in many sexually reproducing organisms, and deserves deeper investigation in the future.
Collapse
Affiliation(s)
- Fabio Manfredini
- School of Biological Sciences, Royal Holloway University of London, Egham, United Kingdom
- Department of Computer Science, and Centre for Systems and Synthetic Biology, Royal Holloway University of London, Egham, United Kingdom
| | - Alfonso E Romero
- Department of Computer Science, and Centre for Systems and Synthetic Biology, Royal Holloway University of London, Egham, United Kingdom
| | - Inti Pedroso
- Center for Systems Biotechnology, Fraunhofer Chile Research Foundation, Santiago, Chile
| | - Alberto Paccanaro
- Department of Computer Science, and Centre for Systems and Synthetic Biology, Royal Holloway University of London, Egham, United Kingdom
| | - Seirian Sumner
- School of Biological Sciences, University of Bristol, United Kingdom
- Present address: Centre for Biodiversity & Environment Research, Department of Genetics, Evolution & Environment, University College London, London, United Kingdom
| | - Mark J F Brown
- School of Biological Sciences, Royal Holloway University of London, Egham, United Kingdom
| |
Collapse
|
11
|
Lucas AR, Richards DY, Ramirez LM, Lutterschmidt DI. Arginine Vasotocin and Neuropeptide Y Vary with Seasonal Life-History Transitions in Garter Snakes. Integr Comp Biol 2017; 57:1166-1183. [DOI: 10.1093/icb/icx107] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
|
12
|
Geographic variation and within-individual correlations of physiological stress markers in a widespread reptile, the common garter snake (Thamnophis sirtalis). Comp Biochem Physiol A Mol Integr Physiol 2017; 205:68-76. [DOI: 10.1016/j.cbpa.2016.12.019] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2016] [Revised: 12/16/2016] [Accepted: 12/16/2016] [Indexed: 01/14/2023]
|
13
|
Nugent BM, Stiver KA, Alonzo SH, Hofmann HA. Neuroendocrine profiles associated with discrete behavioural variation in
Symphodus ocellatus
, a species with male alternative reproductive tactics. Mol Ecol 2016; 25:5212-5227. [DOI: 10.1111/mec.13828] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2015] [Revised: 08/15/2016] [Accepted: 08/23/2016] [Indexed: 12/21/2022]
Affiliation(s)
- B. M. Nugent
- Department of Ecology and Evolutionary Biology Yale University 165 Prospect St. New Haven CT 06520 USA
- Department of Integrative Biology Center for Computational Biology and Bioinformatics The University of Texas at Austin 2415 Speedway Austin TX 78712 USA
| | - K. A. Stiver
- Department of Ecology and Evolutionary Biology Yale University 165 Prospect St. New Haven CT 06520 USA
- Department of Psychology Southern Connecticut State University 501 Crescent St. New Haven CT 06515 USA
| | - S. H. Alonzo
- Department of Ecology and Evolutionary Biology Yale University 165 Prospect St. New Haven CT 06520 USA
- Department of Ecology and Evolutionary Biology University of California Santa Cruz 1156 High St. Santa Cruz CA 95064 USA
| | - H. A. Hofmann
- Department of Integrative Biology Center for Computational Biology and Bioinformatics The University of Texas at Austin 2415 Speedway Austin TX 78712 USA
| |
Collapse
|
14
|
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.
Collapse
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.
| |
Collapse
|
15
|
Dayger CA, Lutterschmidt DI. Seasonal and sex differences in responsiveness to adrenocorticotropic hormone contribute to stress response plasticity in red-sided garter snakes (Thamnophis sirtalis parietalis). J Exp Biol 2016; 219:1022-30. [DOI: 10.1242/jeb.130450] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2015] [Accepted: 01/20/2016] [Indexed: 11/20/2022]
Abstract
Like many vertebrates, hormonal responses to stress vary seasonally in red-sided garter snakes (Thamnophis sirtalis parietalis). For example, males generally exhibit reduced glucocorticoid responses to a standard stressor during the spring mating season. We asked whether variation in adrenal sensitivity to adrenocorticotropic hormone (ACTH) explains why glucocorticoid responses to capture stress vary with sex, season, and body condition in red-sided garter snakes. We measured glucocorticoids at 0, 1, and 4 hours after injection with ACTH (0.1 IU/g body mass) or vehicle in males and females during the spring mating season and fall pre-hibernation period. Because elevated glucocorticoids can influence sex steroids, we also examined androgen and estradiol responses to ACTH. ACTH treatment increased glucocorticoids in both sexes and seasons. Spring-collected males had a smaller integrated glucocorticoid response to ACTH than fall-collected males. The integrated glucocorticoid response to ACTH differed with sex during the spring, with males having a smaller glucocorticoid response than females. Although integrated glucocorticoid responses to ACTH did not vary with body condition, we observed an interaction among season, sex and body condition. In males, ACTH treatment did not alter androgens in either season, but androgens decreased during the sampling period. Similar to previous studies, plasma estradiol was low or undetectable during the spring and fall and therefore any effect of ACTH treatment on estradiol could not be determined. These data provide support for a mechanism that partly explains how the HPA axis integrates information about season, sex, and body condition: namely, variation in adrenal responsiveness to ACTH.
Collapse
Affiliation(s)
- Catherine A. Dayger
- Portland State University, Department of Biology, 1719 SW 10th Ave, Portland, OR 97201, USA
| | | |
Collapse
|