Seasonal photoperiodic influence of pineal melatonin on hypothalamic-pituitary-adrenal axis-hippocampal-receptor in male rats
- Author:
Li WENNA
1
;
Li TING
;
Liu LEILEI
;
Han QI
;
Zhang HAIRONG
;
Sun YIKE
;
Hao RUISEN
;
Ma SHURAN
Author Information
1. School of Traditional Chinese Medicine,Beijing University of Chinese Medicine,Beijing,102488,China
- Keywords:
Pineal gland;
Melatonin;
Hippocampus;
Seasonal photoperiod;
Hypothalamic-pituitary-adrenal axis;
Receptor
- From:
Journal of Traditional Chinese Medical Sciences
2022;9(2):143-152
- CountryChina
- Language:Chinese
-
Abstract:
Background:Based on the effect of seasonal changes on human visceral function,this study investigated the impact of seasonal photoperiod of the pineal body on hypothalamic-pituitary-adrenal axis-hippo-campal-receptor in rats,aiming to reveal the mechanism by which pineal gland melatonin regulates the seasonal secretion of hippocampal neurotransmitters.Methods:Vernal equinox,summer solstice,autumn equinox,and winter solstice were selected as four experimental time points,and rats were randomly divided into normal control group,sham operation group,and pinealectomized group.The seasonal changes in corticotropin-releasing hormone(CRH),adrenocorticotropic hormone(ACTH),corticosterone,hypothalamic melatonin receptor(MTR),and hippocampal corticosterone receptor(CORTR)were examined by enzyme-linked immunosorbent assay.Results:Comparing the same group between different seasons,we showed that in the normal control group,CRH,ACTH,corticosterone,and MTR were higher,while CORTR was lower in autumn and winter than in spring(all P＜.05).Compared with the normal control group,the pinealectomized group showed higher levels of corticosterone(P=.01),MTR(P=.01),and CORTR(P=.03)during spring;reduced levels of MTR and CORTR(both P＜.001)during summer;higher levels of ACTH(P=.001)and MTR(P＜.001),and lower levels of CRH(P=.001),corticosterone(P＜.001),and CORTR(P=.003)during autumn;and lower levels of CRH(P＜.001)and MTR(P=.004),and higher level of ACTH(P＜.001)in winter.Conclusions:Seasonal photoperiod acts on the pineal gland to secrete different levels of melatonin,resulting in seasonal changes in the hypothalamic-pituitary-adrenal axis-hippocampal-receptor,which may be the pathophysiological basis for the onset of seasonal affective disorder.
