ACTH-(1-24) and alpha-MSH antagonize feeding behavior stimulated by kappa opiate agonists.
ACTH-(1-24) and alpha-MSH, intracerebroventricularly (ICV) injected at the doses of 4 and 10 micrograms/animal, respectively, markedly inhibited spontaneous feeding in adult Sprague-Dawley rats, the effect remaining significant for 6-9 hours. At these same doses, ACTH-(1-24) and alpha-MSH abolished the feeding-stimulatory effect of the kappa opiate receptor agonist pentazocine, intraperitoneally (IP) injected at the dose of 10 mg/kg. The same antagonism was obtained by ICV injection of ACTH-(1-24) into rats IP treated with other kappa opiate agonists, bremazocine and tifluadom, at the doses of 1 and 5 mg/kg, respectively. These data suggest that melanocortin peptides play an inhibitory role in the complex regulation of food intake, and further support and extend the hypothesis of a melanocortin-opioid homeostatic system, its two neuropeptide components usually having opposite, mutually-balancing effects.
D000324:Adrenocorticotropic Hormone / Q000494:pharmacology*; D000818:Animals; D001569:Benzodiazepines / Q000037:antagonists & inhibitors / Q000494:pharmacology*; D001575:Benzomorphans / Q000037:antagonists & inhibitors / Q000494:pharmacology*; D003366:Cosyntropin / Q000494:pharmacology*; D005247:Feeding Behavior / Q000187:drug effects*; D008297:Male; D009074:Melanocyte-Stimulating Hormones / Q000494:pharmacology*; D009019:Morphinans / Q000494:pharmacology*; D010423:Pentazocine / Q000037:antagonists & inhibitors / Q000494:pharmacology*; D051381:Rats; D011919:Rats, Inbred Strains
D001575:Benzomorphans; D009019:Morphinans; D001569:Benzodiazepines; D003366:Cosyntropin; D000324:Adrenocorticotropic Hormone; D009074:Melanocyte-Stimulating Hormones; C027248:bremazocine; D010423:Pentazocine; C035470:tifluadom