α-MSH effects on novelty-induced defecation, plasma 11-OHCS and whole brain catecholamines in hypophysectomized rats

• Published in: Pharmacology, biochemistry and behavior Vol. 12; no. 5; pp. 773 - 779
• Main Authors: Datta, Purna C., King, Maurice G.
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 01.05.1980
• Subjects: 11-Hydroxycorticosteroids - blood; Animals; Avoidance Learning - drug effects; Brain Chemistry - drug effects; Catecholamines - metabolism; Defecation; Defecation - drug effects; Dopamine - metabolism; Hypophysectomy; Melanocyte-Stimulating Hormones - pharmacology; Norepinephrine - metabolism; Novelty; Plasma 11-OHCS; Rats; Whole brain DA; Whole brain NE; α-MSH; Plasma 11-OHCS; Whole brain NE; Hypophysectomy; α-MSH; Whole brain DA; Defecation; Novelty
• ISSN: 0091-3057; 1873-5177
• DOI: 10.1016/0091-3057(80)90165-3

The effect of hypophysectomy on novelty-induced defacation was found to be inhibitory in nature, but this effect was reversed by treatment with α-MSH. MSH-treated hypox rats maintained, over days, novelty-induced defecation and showed a significant elevation in plasma 11-OHCS levels, compared with the levels of control-injected counterparts. MSH treatment also reduced over Days 1 to 5 the whole brain DA and whole brain NE levels in hypox animals. Control-treated hypox rats, however, showed an increase in brain NE concentration which was significantly reduced by MSH treatment. Sham-hypox animals also sustained novelty-induced defecation after MSH treatment but did not show a significant rise in plasma 11-OHCS level. Whole brain DA and whole brain NE levels in sham-hypox rats were also reduced significantly by MSH treatment. The behavioral maintenance of defecation in hypox and sham-hypox rats seem to be concomitant with significant reductions in whole brain catecholamines.