褪黑素受体与GABAA受体在褪黑素延长小鼠睡眠时间中的作用

目的：研究褪黑素受体和GABAA受体在褪黑素延长小鼠睡眠时间中的作用。方法：以翻正反射消失为睡眠开始的指标,至翻正反射恢复作为睡眠时间。观察不同受体激动剂或拮抗剂对褪黑素催眠作用的影响。结果：褪黑素3型受体拮抗剂盐酸哌唑嗪对褪黑素延长小鼠睡眠时间的作用无明显影响。GABA受体内源性激动剂GABA能明显增强褪黑素延长小鼠睡眠时间的作用,而GABAA受体上的印防己毒素结合位点的配基,即氯离子通道阻断剂印防己毒素能明显拮抗褪黑素的催眠作用,GABAA受体上的GABA结合位点的拮抗剂荷包牡丹碱则对褪黑素延长小鼠睡眠作用无明显影响。结论：褪黑素延长小鼠睡眠时间的作用与褪黑素3型受体无关,而与GABAA受体关系密切,其作用主要由印防己毒素结合位点介导。

The role of melatonin receptor and GABAA receptor in the sleeping time prolonged by melatonin in mice

Aim: To observe the role of melatonin receptor and GABA A receptor in s leeping time prolonged by melatonin in mice. Methods: The absenc e of the righting reflex was considered as the sleep onset and the duration of t he loss of the righting reflex was recorded as the sleeping time. The effects of receptor agonist and antagonist on hypnotic activity of melatonin were studied in the paper. Results: Prazosin hydrochloride, the blocker of me latonin 3 receptor, didn't affect the sleeping time prolonged by melatonin in mi ce. GABA, the endogenous agonist of GABA receptor, significantly potentiated the hypnotic activity of melatonin. When picrotoxin, the ligand of picrotoxin site on GABA A receptor, used together with melatonin, it significantly antagonized the sleeping time prolonged by melatonin, however, bicuculline, the specific ant agonist of GABA binding site in GABA A receptor, didn't affect the hypnotic a ctivity of melatonin in mice. Conclusion: Melatonin does not exh ibit its potentiation sleeping time in mice through melatonin 3 receptor. Hypnot ic activity of melatonin may be mediated through picrotoxin site on GABA A rece ptor.