Effect of beta-adrenoceptors on the behaviour induced by the neuropeptide glutamic acid isoleucine amide.
Excessive grooming behaviour is induced by intracerebroventricular injections of the neuropeptide glutamic acid isoleucine amide (neuropeptide-EI), via the activation of A-10 dopaminergic neurons and the noradrenergic system. Our object was to study the latter system involved in these behaviours, using male Wistar rats weighing 250-300 g with i.c.v. implants. The results show that all the adrenoceptor antagonists "per se" do not affect excessive grooming behaviour or motor activity. Intracerebroventricular administration of propranolol, a general beta-adrenoceptor antagonist, before neuropeptide-EI, inhibited the induced excessive grooming behaviour in a dose dependent manner. Metoprolol, a beta(1)-adrenoceptor antagonist, also blocked this behaviour. However, intracerebroventricular injections of phentolamine, an alpha-adrenoceptor antagonist, and ((+/-)-1-[2,3-(Dihydro-7-methyl-1H-inden-4-yl)oxy]-3-[(1-methylethyl)amino]-2-butanol), a beta(2)-adrenoceptor antagonist, had no effect on the behaviour induced by neuropeptide-EI induced behaviour for any of the doses tested. On the other hand, isoproterenol, a general beta-adrenoceptor agonist and dobutamine, a beta(1)-adrenoceptor agonist, both elicited similar behaviours as those induced by neuropeptide-EI. These results support the hypothesis that a relationship exists between neuropeptide-EI and beta-adrenoceptors, more specifically the beta(1)-adrenoceptor, as found with other similar endogenous peptides such as neurotensin, cholecystin, substance P and alpha-melanocyte stimulating hormone. Hence, neuropeptide-EI could probably be exerting a neuromodulating effect on the central nervous system.
Sánchez-Borzone
Mariela E
ME
Laboratorio de Ciencias Fisiológicas, Cátedra de Bacteriología y Virología Médica, Facultad de Ciencias Médicas, Universidad Nacional de Córdoba, Santa Rosa 1085, Córdoba C.P. 5000, Argentina.
Attademo
Andrés
A
Baiardi
Gustavo
G
Celis
María Ester
ME
D000317:Adrenergic alpha-Antagonists / Q000494:pharmacology; D058665:Adrenergic beta-1 Receptor Agonists; D058671:Adrenergic beta-1 Receptor Antagonists; D000318:Adrenergic beta-Agonists / Q000494:pharmacology; D000319:Adrenergic beta-Antagonists / Q000494:pharmacology; D000818:Animals; D001522:Behavior, Animal / Q000187:drug effects; D004280:Dobutamine / Q000494:pharmacology; D006120:Grooming / Q000187:drug effects*; D007545:Isoproterenol / Q000494:pharmacology; D008297:Male; D008790:Metoprolol / Q000494:pharmacology; D009043:Motor Activity / Q000187:drug effects*; D009842:Oligopeptides / Q000494:pharmacology*; D010646:Phentolamine / Q000494:pharmacology; D011433:Propranolol / Q000494:pharmacology; D051381:Rats; D017208:Rats, Wistar; D018342:Receptors, Adrenergic, beta-1 / Q000378:metabolism*
D000317:Adrenergic alpha-Antagonists; D058665:Adrenergic beta-1 Receptor Agonists; D058671:Adrenergic beta-1 Receptor Antagonists; D000318:Adrenergic beta-Agonists; D000319:Adrenergic beta-Antagonists; D009842:Oligopeptides; D018342:Receptors, Adrenergic, beta-1; C522850:neuropeptide EI; D004280:Dobutamine; D011433:Propranolol; D008790:Metoprolol; D007545:Isoproterenol; D010646:Phentolamine