Effects of MIF-I and melatonin on novelty-induced defecation and associated plasma 11-OHCS and brain catecholamines.
In two experiments the effects were investigated of MSH-inhibiting factor-I (MIF-I) and of Melatonin on step-down latencies, defection, plasma 11-OHCS levels, whole brain DA and whole brain NE concentrations on Days 1, 3 and 5 of novelty exposure. Treatment with MIF-I led to a significant habituation of novelty-induced defecation over 5 days, whereas plasma 11-OHCS level was reduced only on Day 1. The concentrations of whole brain DA and whole brain NE also showed a significant increase over days of MIF-I and novelty treatment. Melatonin treatment, on the other hand, significantly inhibited novelty-induced defecation and reduced plasma 11-OHCS level on Day 5 of novelty exposure. Melatonin treatment led to a significant increase of whole brain DA in animals exposed to novelty for 5 days. Neither MIF-I nor Melatonin was found to significantly affect the step-down activity of treated animals. The overall results suggested a possible relationship between novelty-induced defecation and brain DA levels of MIF-I and Melatonin treated animals.
D015062:11-Hydroxycorticosteroids / Q000097:blood*; D000818:Animals; D001923:Brain Chemistry / Q000187:drug effects*; D002395:Catecholamines / Q000378:metabolism*; D003672:Defecation / Q000187:drug effects*; D004777:Environment; D009075:MSH Release-Inhibiting Hormone / Q000494:pharmacology*; D008297:Male; D008550:Melatonin / Q000494:pharmacology*; D051381:Rats; D013997:Time Factors
D015062:11-Hydroxycorticosteroids; D002395:Catecholamines; D009075:MSH Release-Inhibiting Hormone; D008550:Melatonin