Abe H, Honma S, Shinohara K, Honma K
Department of Physiology, Hokkaido University School of Medicine, Sapporo, Japan.
Brain Res. 1996 Feb 5;708(1-2):135-42. doi: 10.1016/0006-8993(95)01298-2.
Substance P (SP) is a candidate neurotransmitter or neuromodulator for conveying light information from the retina to the hypothalamic suprachiasmatic nucleus (SCN) where a circadian oscillator(s) is located in mammals. Immediate early gene c-fos has been demonstrated to be induced in the SCN with a brief light exposure at the subjective night, and suggested to play an important role in the photic entrainment of the oscillator. To clarify the possibility of an involvement of the SP receptor in the photic-induction of c-fos in the SCN, we examined effects of a SP receptor antagonist, spantide, on the light-induced Fos-like protein immunoreactivity (Fos-lir) in the SCN of Syrian hamster. The light-induced Fos-lir was inhibited with the pretreatment of spantide in a dose-related manner and in an anatomically distinctive way. The higher dose of spantide (8 nmol) blocked light-induced Fos-lir substantially in the rostral and central areas of the SCN, and in the dorsal portion of the caudal SCN. However, it blocked Fos-lir only slightly in the ventral portion of the caudal SCN. These results suggest that the SP is involved in conveying light information to induce Fos protein in the hamster SCN, and that different neurotransmitter systems are involved in the light-induced Fos-lir in the different portions of hamster SCN.
P物质（SP）是一种候选神经递质或神经调质，用于在哺乳动物中将光信息从视网膜传递至下丘脑视交叉上核（SCN），而生物钟振荡器位于该核中。即刻早期基因c-fos已被证明在主观夜间短暂光照下会在SCN中被诱导表达，并被认为在振荡器的光诱导同步中起重要作用。为了阐明SP受体是否参与SCN中c-fos的光诱导过程，我们研究了SP受体拮抗剂spantide对叙利亚仓鼠SCN中光诱导的Fos样蛋白免疫反应性（Fos-lir）的影响。spantide预处理以剂量相关的方式并以解剖学上独特的方式抑制了光诱导的Fos-lir。较高剂量的spantide（8 nmol）在很大程度上阻断了SCN头端和中央区域以及尾端SCN背侧部分的光诱导Fos-lir。然而，它仅轻微阻断了尾端SCN腹侧部分的Fos-lir。这些结果表明，SP参与了在仓鼠SCN中传递光信息以诱导Fos蛋白，并且不同的神经递质系统参与了仓鼠SCN不同部分的光诱导Fos-lir。
