Takahashi H
Naunyn Schmiedebergs Arch Pharmacol. 1985 May;329(3):222-6. doi: 10.1007/BF00501872.
The possible central regulation of cardiovascular system by serotoninergic neurones was investigated in rats by using a cross-circulated head preparation. Intracarotid injections of serotonin (5-HT, 0.1-10 micrograms) consistently produced neurally mediated vasodepression in the recipient body. Although intravenous injections of 5-HT (0.1-1 micrograms) caused similar depressor responses, larger doses (5-10 micrograms) caused biphasic responses, consisting of vasodepression followed by a sustained pressor response. Despite the biphasic blood pressure responses, sympathetic nerve activity was consistently reduced by the intravenous 5-HT. Bilateral vagotomy abolished the vasodepressor responses to intravenous injections of 5-HT (10 micrograms) and made the responses purely pressor, but the vasodepressor responses to intracarotid injections of 5-HT (10 micrograms) were largely unaffected. Following destruction of central noradrenergic neurones by intracerebroventricular injections of 6-hydroxydopamine, the vasodepressor responses to intracarotid 5-HT (1-10 micrograms), but not to the intravenous 5-HT, were significantly reduced. These results suggest that intravenous injections of 5-HT reduce nerve activity by affecting the reflex mechanism via the vagus nerves. On the other hand, the vasodepression and reduction of the nerve activity by the intracarotid injections appears to be of central origin, and the vasodepression could be mediated via noradrenergic mechanisms in the brain.
采用交叉循环头部制备法在大鼠中研究了5-羟色胺能神经元对心血管系统可能的中枢调节作用。颈内注射5-羟色胺（5-HT，0.1 - 10微克）在受体动物体内持续产生神经介导的血管减压反应。虽然静脉注射5-HT（0.1 - 1微克）引起类似的降压反应，但较大剂量（5 - 10微克）引起双相反应，包括血管减压反应后接着是持续的升压反应。尽管有双相血压反应，但静脉注射5-HT可使交感神经活动持续降低。双侧迷走神经切断术消除了对静脉注射5-HT（10微克）的血管减压反应，并使反应纯粹为升压反应，但对颈内注射5-HT（10微克）的血管减压反应基本不受影响。经脑室注射6-羟基多巴胺破坏中枢去甲肾上腺素能神经元后，对颈内注射5-HT（1 - 10微克）的血管减压反应显著降低，但对静脉注射5-HT的反应未受影响。这些结果表明，静脉注射5-HT通过影响迷走神经的反射机制来降低神经活动。另一方面，颈内注射引起的血管减压和神经活动降低似乎源于中枢，且血管减压可能通过脑中的去甲肾上腺素能机制介导。
