The effect of beta-(Tyr9)melanotropin-(9-18) on the active avoidance and open-field behavior on rats pretreated with atropine or propranolol.
beta-(Tyr9)melanotropin-(9-18) inhibited the extinction of active avoidance behavior. The muscarinic cholinergic blocker atropine did not influence the peptide-induced inhibition, whereas the beta-receptor blocker propranolol decreased it. Furthermore, the peptide increased the ambulation of the animals. Neither the muscarinic blocker nor the beta-blocker had any action on this effect of beta-(Tyr9)melanotropin-(9-18). Atropine markedly decreased the defecation of the animals, and this effect was not influenced by the peptide. The results suggest that the beta-receptors play an important role in the inhibition of extinction induced by the peptide, however, the actions on the open-field activity are mediated by different mechanisms.
D000818:Animals; D001285:Atropine / Q000494:pharmacology*; D001362:Avoidance Learning / Q000187:drug effects*; D001522:Behavior, Animal / Q000187:drug effects*; D008297:Male; D009074:Melanocyte-Stimulating Hormones / Q000494:pharmacology*; D009043:Motor Activity / Q000187:drug effects; D010446:Peptide Fragments / Q000494:pharmacology*; D011433:Propranolol / Q000494:pharmacology*; D051381:Rats; D011943:Receptors, Adrenergic, beta / Q000187:drug effects; D011976:Receptors, Muscarinic / Q000187:drug effects
D010446:Peptide Fragments; D011943:Receptors, Adrenergic, beta; D011976:Receptors, Muscarinic; C033533:MSH, beta, (9-18), Tyr(9)-; D001285:Atropine; D009074:Melanocyte-Stimulating Hormones; D011433:Propranolol