Effect of arousing stimuli on circulating corticosterone and the circadian rhythms of luteinizing hormone (LH) surges and locomotor activity in estradiol-treated ovariectomized (ovx + EB) Syrian hamsters |
| |
| Institution: | 1. Department of Physiology, University of Kentucky, 800 Rose Street, Lexington, KY 40536-0298, USA;2. Department of Anatomy and Neurobiology, University of Kentucky, 800 Rose Street, Lexington, KY 40536-0298, USA;1. Cellular and Integrative Physiology, University of Nebraska Medical Center, Omaha, NE, USA.;2. Department of Anesthesiology, University of Nebraska Medical Center, Omaha, NE, USA.;1. CIAFEL – Research Centre in Physical Activity, Health and Leisure, Laboratory of Biochemistry and Experimental Morphology, Faculty of Sport, University of Porto, R. Dr. Plácido da Costa 91, 4200-450 Porto, Portugal;2. CITAB – Centre for the Research and Technology of Agro-Environment and Biological Sciences, University of Trás-os-Montes e Alto Douro, 5001- 801 Vila Real, Portugal;3. Department of Physical Therapy, Federal University of Pernambuco; Av. Prof. Moraes Rego, 1235 - University City, Recife, Pernambuco, 50670, Brazil;1. Key Laboratory of Zoonosis, Ministry of Education, Institute of Zoonosis, China-Japan Union Hospital, Jilin University, Changchun 130062, PR China;2. State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin 150001, PR China;3. Second Hospital of Jilin University, Changchun, Jilin Province 130021, PR China;4. Fourth Hospital of Jilin University, Changchun 130062, PR China;5. Jiangsu Co-Innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou 225009, PR China |
| |
| Abstract: | In most proestrous hamsters, novel wheel exposure phase advances activity rhythms and blocks the preovulatory LH surge, which occurs 2 h earlier the next day. Because wheel immobilization does not prevent these effects we hypothesized that arousal alone blocks and phase advances the LH surge. Ovariectomized (ovx) hamsters received a jugular vein cannula and estradiol benzoate (EB) or vehicle was injected sc. The next day (Day 1), at zeitgeber time (ZT) 4–5 (ZT 12 = lights off), after obtaining a blood sample, each hamster was exposed to constant darkness (DD), and either remained in her home cage or was transferred to a new cage and exposed to a running wheel or a 2-hour arousal paradigm. Blood samples were obtained in dim red light and activity was recorded hourly until ~ ZT 10–11 on Days 1 and 2. For the next 1–2 weeks, activity was monitored in DD. Plasma LH and corticosterone were assessed by RIA. Novel wheel exposure or arousal at ZT 4 greatly attenuated the Day 1 LH surge in ovx + EB hamsters, and phase advanced the Day 2 LH surge by about 2 h. In proestrous hamsters, novel wheel exposure led to a prolonged (> 2 h) increase in corticosterone levels only when LH surges were blocked. Phase advances in activity rhythms were enhanced by estradiol and arousal. The results suggest that estradiol modulates the effectiveness of non-photic stimuli. The role of the increased activity of the hypothalamic–pituitary–adrenal axis associated with novel wheel-induced attenuation of LH surges in ovx + EB hamsters remains to be determined. |
| |
| Keywords: | |
| 本文献已被 ScienceDirect 等数据库收录！ |
|
