Two types of VIP neuronal components in rat suprachiasmatic nucleus

✍ Scribed by Kunihiko Kawamoto; Mamoru Nagano; Fumio Kanda; Kazuo Chihara; Yasufumi Shigeyoshi; Hitoshi Okamura

• Book ID: 102384142
• Publisher: John Wiley and Sons
• Year: 2003
• Tongue: English
• Weight: 243 KB
• Volume: 74
• Category: Article
• ISSN: 0360-4012
• DOI: 10.1002/jnr.10751

✦ Synopsis

Vasoactive intestinal peptide (VIP) neurons constitute a large group in the suprachiasmatic nucleus (SCN) and it is thought that they are involved in the generation and entrainment of circadian rhythm. We have characterized these VIP-expressing neurons in rat SCN by their ability to induce the mammalian Period1 (Per1) gene in response to light exposure, innervation of retinal afferents, day-night variations in VIP mRNA, and coexpression of gastrin releasing peptide (GRP). VIP neurons in the ventrolateral SCN (SCN VL ) were subdivided into two groups, light-evoked Per1-inducible main SCN VL (SCN VLmain ) and non-Per1-inducible medially located SCN VL (SCN VLmed ). Retinal innervation was abundant in the SCN VLmain but nearly absent in the SCN VLmed . Day-night variation in VIP mRNA expression level was observed in the SCN VLmain but not in the SCN VLmed . GRP mRNA was seen in rarely SCN VLmed but abundant in SCN VLmain , where some neurons coexpressed VIP mRNA. These findings indicate that VIP neurons in the SCN can be divided into two topographically and functionally distinct groups.