title: Effects of melanocyte-stimulating hormone (MSH) and melatonin on passive avoidance and on an emotional response.
abstract: The present experiment investigated the opposite effects of synthetic alpha-MSH and Melatonin on acquisition and extinction of a passive avoidance response (PAR) and on emotionality, as indexed by defecation, in the PA box. It was found that intraperitoneal (IP) administration of alpha-MSH delayed extinction and increased defecation responses whereas IP administration of Melatonin facilitated extinction of the PAR and decreased defecation. The present experiment confirmed MSH-Melatonin opposition on memory and on the defecation response.
mesh_terms: D000818:Animals; D001362:Avoidance Learning / Q000187:drug effects*; D003672:Defecation / Q000187:drug effects; D004644:Emotions / Q000187:drug effects*; D005108:Extinction, Psychological / Q000187:drug effects; D008297:Male; D009074:Melanocyte-Stimulating Hormones / Q000494:pharmacology*; D008550:Melatonin / Q000494:pharmacology*; D051381:Rats; D013997:Time Factors
chemical_list: D009074:Melanocyte-Stimulating Hormones; D008550:Melatonin