日大医学雑誌

コルチコステロンのラット海馬錐体細胞の
セロトニン 1A 受容体機能に及ぼす影響
―無麻酔,無拘束下での電気生理学的,行動薬理学的検討―

原著

著者

松  崎  大  和
日本大学医学部精神医学講座

要旨

We have previously shown that a both 5-HT1A agonist drug (buspirone) and selective serotonin reuptake inhibitor(sertraline) produced suppressions of hippocampal CA1 pyramidal neurons through stimulating 5-HT1A receptors inunanaesthetized, unrestrained rats. In the present study, we evaluated the effects of corticosterone on both buspirone andsertraline-induced suppressions of hippocampal CA1 pyramidal neurons. The acute administration of corticosterone (0.5,5, and 50 mg/kg) had no effect on the spontaneous firing activities of hippocampal CA1 pyramidal neurons. Corticosteronepretreatments (5 mg/kg and 50 mg/kg) attenuated the buspirone-induced suppression of hippocampal CA1 pyramidalneurons, indicating inhibition of postsynaptic 5-HT1A receptor functions. Corticosterone pretreatment also attenuatedthe sertraline-induced suppression of pyramidal neurons at 5 mg/kg. Previous behavioral experiments indicated that theactivation of 5-HT1A receptors in the hippocampus interferes with the acquisition of contextual fear memories. We alsoassessed the effects of corticosterone on 5-HT1A functions using a behavioral model. Subcutaneous administration ofbuspirone (3 mg/kg), when injected before conditioning, decreased the freezing behavior induced by contextual stimuli.Corticosterone (50 mg/kg) attenuated the impairment of fear conditioning induced by buspirone. Our results suggest thatcorticosterone suppresses 5-HT1A receptor functions in the hippocampus.

keyword

corticosterone, 5-HT1A receptor, dorsal hippocampus CA1 pyramidal neuron, conditioned fear stress,
single unit-recording
コルチコステロン,5-HT1A 受容体,海馬 CA1 錐体細胞,恐怖条件付けストレス,単一細胞
外記録