Prosser R A, Miller J D, Heller H C
Department of Biological Sciences, Stanford University, CA 94305.
Brain Res. 1990 Nov 26;534(1-2):336-9. doi: 10.1016/0006-8993(90)90153-3.
The mammalian circadian pacemaker in the suprachiasmatic nuclei (SCN) receives a large serotonergic (5-HTergic) projection from the raphe nuclei. Whether the SCN pacemaker can be modulated by this afferent projection is a question of considerable theoretical and practical interest. In this study we investigated whether the 5-HT agonist, quipazine, can reset the phase of the SCN clock when it is isolated in vitro. Our results show that 1 h treatments with quipazine induce robust phase shifts in vitro, and that this effect depends upon the circadian time of treatment. We further show that the ability of quipazine to induce phase shifts is dose-dependent. These results suggest that the SCN circadian pacemaker is sensitive to 5-HTergic stimulation, and therefore that the 5-HTergic projection to the SCN may play a role in modulating the phase of the SCN clock in the intact animal.
哺乳动物视交叉上核（SCN）中的昼夜节律起搏器接收来自中缝核的大量5-羟色胺能（5-HT能）投射。SCN起搏器是否能被这种传入投射所调节是一个具有相当理论和实际意义的问题。在本研究中，我们调查了5-HT激动剂喹哌嗪在体外分离时能否重置SCN时钟的相位。我们的结果表明，用喹哌嗪处理1小时可在体外诱导强烈的相位偏移，且这种效应取决于处理的昼夜节律时间。我们进一步表明，喹哌嗪诱导相位偏移的能力是剂量依赖性的。这些结果表明，SCN昼夜节律起搏器对5-HT能刺激敏感，因此，向SCN的5-HT能投射可能在调节完整动物中SCN时钟的相位方面发挥作用。
