Intraventricular Injection of Melatonin Inhibits Naloxone- Induced, but not NMDA- or LHRH-Induced LH Release in Ovariectomized Estrogen-Primed Rats

Endocrine Journal

TATSUO AKEMA²  JUN-ICHI TOYODA²  IZUMI SATO²  HITOSHI SUGIYAMA²  TOMOYUKI IKEDA²  ATSUHIKO CHIBA³  FUKUKO KIMURA¹ 

[1] Department of Physiology, Yokohama City University School of Medicine;Department of Physiology, St. Marianna University School of Medicine;Life Science Institute, Sophia University

关键词: Melatonin;    Naloxone;    NMDA;    LHRH;    LH;   

DOI  :  10.1507/endocrj.46.831

学科分类：内分泌与代谢学

来源: Japan Endocrine Society

【 摘 要 】

References(30)Cited-By(2)The present study was aimed to examine the possible functional relationship between melatonin and hypothalamic transmitters, endogenous opioids and excitatory amino acids in controlling gonadotropin secretion in ovariectomized estrogen-primed rats. An intravenous injection of naloxone (μ opioid receptor antagonist), N-methyl-D-aspartate (NMDA; NMDA receptor agonist) or luteinizing hormone-releasing hormone (LHRH) significantly elevated serum luteinizing hormone (LH) concentrations within 10min. An intraventricular treatment with melatonin, which did not affect the basal LH concentration by itself, significantly suppressed the effect of naloxone. However, the same melatonin treatment did not inhibit the NMDA-induced or LHRH-induced LH secretion. These results support the hypothesis that melatonin has a suprapituitary site of action to inhibit LHRH release, and suggest that the site of its action may be located downstream to that of naloxone action and upstream to that of NMDA in the hypothalamic LHRH neuronal pathway.

【 授权许可】

Unknown