Circadian Rhythms in the Function of Central Serotonin Receptors

1. 研究了大鼠对选择性5-羟色胺（5-HT） 1A受体激动剂8-OH-DPAT行为反应的昼夜节律。(1)大鼠在不同时间SC注射8-OH-DPAT。结果，在8-OH-DPAT的行为（5-HT综合征）反应中发现了昼夜节律。(2)研究8-OH-DPAT对大鼠脑室内行为反应的昼夜节律。结果表明，昼夜节律的存在与在SC给药的行为反应中观察到的模式相似。这些观察结果表明，中枢突触后5-HT1A受体在其功能中表现出昼夜节律。(3)在连续黑暗（DD）条件下观察8- oh - dpat诱导的大鼠行为综合征。结果显示，在DD条件下，8-OH-DPAT的行为反应具有昼夜节律。这种节奏的模式与在明暗条件下观察到的相似。这些结果强烈表明，中枢5-HT1A受体的功能节律是由内源性振荡器驱动的。(4)通过观察低温观察8-OH-DPAT反应性的节律变化。低温反应表现出明显的昼夜节律。观察到的节律波形与5-HT综合征的节律波形相似。证据进一步支持中枢突触后5-HT1A受体功能表现出昼夜节律。研究了SC给予选择性5-HT2A/2C受体激动剂DOI的行为反应中的昼夜节律。在doi诱导的湿狗震动反应中观察到昼夜节律。脑室内给药DOI提示类似的结果。这些结果表明，中枢5-HT2A受体的功能具有昼夜节律。

1. Circadian rhythm in the behavioral responsiveness to the selective serotonin (5-HT) 1A receptor agonist 8-OH-DPAT was studied in rats.(1) Rats were SC injected with 8-OH-DPAT at different times of day. As a result, circadian thythm was found in behavioral (5-HT syndrome) response to 8-OH-DPAT.(2) Circadian rhythms were investigated in the behavioral responses to intracerebroventricular administration of 8-OH-DPAT in rats. The results indicated the existence of circadian rhythms of a similar pattern to those observed in the behavioral responses to SC administration of the drug. These observations suggest that the central postsynaptic 5-HT1A receptor exhibits a circadian rhythm in its function.(3) The 8-OH-DPAT-induced behavioral syndrome was examined in rats kept under continuous dark (DD) conditions for six days. The results revealed a circadian rhythm in the behavioral response to 8-OH-DPAT under DD conditions. The pattern of this rhythm was similar to that observed under the light-dark conditions. These results strongly suggest that the rhythm in the function of central 5-HT1A receptors is driven by the endogenous oscillator.(4) The rhythm was examined in the responsiveness to 8-OH-DPAT by observing hypothermia. The hypothermic response displayd significant circadian rhythms. The waveform of the rhythms observed was similar to that of the rhythms in the 5-HT syndrome. The evidence further supports that the central postsynaptic 5-HT1A receptor function exhibits a circadian rhythm.2. The circadian rhythm was investigated in the behavioral response to the SC administration of selective 5-HT2A/2C receptor sgonist DOI.A circadian rhythm was observed in the DOI-induced wet-dog shake response. Intracerebroventricular administration of DOI suggested the similar results. These results suggest that the function of the central 5-HT2A receptor exhibits a circadian rhythm.