Melatonin potentiates 5-HT1A receptor activation in rat hypothalamus and results in hypothermia
Melatonin potentiates 5-HT1A receptor activation in rat hypothalamus and results in hypothermia
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DOI：
10.1034/j.1600-079x.2002.01867.x
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发表时间：
2002-08-01
影响因子：
10.3
通讯作者：
Chuang, JI
中科院分区：
文献类型：
--
作者：
Lin, MT;Chuang, JI
褪黑素对未麻醉大鼠在三种不同环境温度下的体温调节反应和下丘脑血清素释放的影响进行了评估（T (a)）。全身给药褪黑激素（30- 120mg /kg, i.p）导致大鼠在T (a) 8和22℃时结肠温度和下丘脑5-羟色胺（5-HT）释放降低。体温8℃时代谢率降低引起体温过低，而体温22℃时代谢率降低和皮肤温度升高同时引起体温过低。然而，在高温条件下（T (a) 31℃），同样剂量的褪黑激素既不影响体温调节反应，也不影响下丘脑5-羟色胺的释放。通过脑室内注射5,7-二羟色胺选择性地消耗脑5- ht，可以减轻褪黑素诱导的低温和下丘脑5- ht释放的减少。此外，使用5-HT2A受体激动剂（DOI）或5-HT1A受体拮抗剂[(-)-pindolol]治疗后，褪黑素诱导的低温几乎完全消失。这些数据表明，褪黑激素增强了下丘脑5-HT1A受体的激活，并导致低温效应，而这种效应可以被DOI预期的高温效应所拮抗。
Effects of melatonin on both thermoregulatory responses and hypothalamic serotonin release were assessed in unanesthetized rats at three different ambient temperatures (T (a) ). Systemic administration of melatonin (30-120 mg/kg, i.p) caused a decrease in both colonic temperature and hypothalamic serotonin (5-HT) release in rats at both T (a) 8 and 22degreesC. The hypothermia was brought about by a decrease in metabolic rate at T (a) 8degreesC, whereas at T (a) 22degreesC the hypothermia was produced by both a decrease in metabolic rate and an increase in cutaneous temperature. However, in the heat (T (a) 31degreesC), neither thermoregulatory responses nor hypothalamic 5-HT release was affected by the same amount of administered melatonin. The melatonin-induced hypothermia and decreased 5-HT release in the hypothalamus were attenuated by selective depletion of brain 5-HT produced by intracerebroventricular injection of 5,7-dihydroxytryptamine. Furthermore, the melatonin-induced hypothermia was almost completely abolished by treatment with a 5-HT2A receptor agonist (DOI) or a 5-HT1A receptor antagonist [(-)-pindolol]. The data indicate that melatonin potentiates the 5-HT1A receptor activation in the hypothalamus and results in hypothermic effects which can be antagonized by the expected hyperthermic effect of DOI.