The influence of serotonergic inputs on peptide neurons in the rat suprachiasmatic nucleus: an immunocytochemical study.
The influence of serotonin (5-hydroxytryptamine; 5-HT) innervation on peptide-containing neurons in the rat suprachiasmatic nucleus (SCN) was investigated by peroxidase-anti-peroxidase (PAP) immunocytochemistry. The 5-HT neuronal system was chemically severed by 5,6-dihydroxytryptamine (5,6-DHT) injection into the medial forebrain bundle bilaterally. After this treatment, a marked decrease of vasoactive intestinal peptide (VIP)-like immunoreactivity in neuronal perikarya occurred in the SCN corresponding to a decrease in number of 5-HT immunoreactive fibers and terminals. However, no alteration of arginine-vasopressin-like immunoreactivity was detected between 5,6-DHT-treated animals and the controls. It is speculated that VIP-like immunoreactive neurons play an important role in the SCN under the influence of strong 5-HT innervation.
D015115:5,6-Dihydroxytryptamine / Q000494:pharmacology; D000818:Animals; D001127:Arginine Vasopressin / Q000378:metabolism; D007124:Immunoenzyme Techniques; D008297:Male; D051381:Rats; D011919:Rats, Inbred Strains; D012701:Serotonin / Q000378:metabolism*; D013493:Suprachiasmatic Nucleus / Q000378:metabolism*; D014660:Vasoactive Intestinal Peptide / Q000378:metabolism
D001127:Arginine Vasopressin; D012701:Serotonin; D014660:Vasoactive Intestinal Peptide; D015115:5,6-Dihydroxytryptamine