Kawano S, Osaka T, Kannan H, Yamashita H
Department of Physiology, University of Occupational and Environmental Health, Kitakyushu, Japan.
Brain Res Bull. 1992 Apr;28(4):573-9. doi: 10.1016/0361-9230(92)90105-7.
Extracellular recordings were made from 467 anti-dromically identified neurosecretory neurons and 148 non-neurosecretory neurons in the paraventricular nucleus of the hypothalamus of hemispherectomized cats under pentobarbital anesthesia. Stimulation of the dorsal, median, and pontine raphe nuclei excited 31%, 26%, and 12% of neurosecretory neurons tested, respectively, and inhibited 9%, 7%, and 8%. The excitatory responses in 13 of 14 neurons tested were blocked by either of two intravenously administered 5-HT2 antagonists, cyproheptadine or methysergide. The 5-HT1A antagonist, (-)pindolol, partially blocked the excitatory responses elicited by raphe stimulation in three of five neurons tested. The inhibitory responses to raphe stimulation were not affected by application of these antagonists. More non-neurosecretory neurons than neurosecretory neurons were excited in response to raphe stimulation and these excitatory responses were also blocked by these antagonists. We conclude that most electrically stimulated synaptic inputs from the midbrain raphe nuclei to the hypothalamic paraventricular nucleus are excitatory and are mainly mediated by 5-HT2 receptors.
在戊巴比妥麻醉下，对大脑半球切除猫下丘脑室旁核中467个经逆向鉴定的神经分泌神经元和148个非神经分泌神经元进行了细胞外记录。刺激背侧、中缝和脑桥中缝核分别使所测试的神经分泌神经元兴奋31%、26%和12%，并使其抑制9%、7%和8%。在14个被测试的神经元中，13个神经元的兴奋反应被静脉注射的两种5-HT2拮抗剂之一（赛庚啶或甲基麦角新碱）阻断。5-HT1A拮抗剂（-）吲哚洛尔部分阻断了在5个被测试神经元中3个神经元由中缝刺激引发的兴奋反应。对中缝刺激的抑制反应不受这些拮抗剂应用的影响。与神经分泌神经元相比，更多的非神经分泌神经元对中缝刺激产生兴奋反应，并且这些兴奋反应也被这些拮抗剂阻断。我们得出结论，从中脑缝核到下丘脑室旁核的大多数电刺激突触输入是兴奋性的，并且主要由5-HT2受体介导。
