Participation of the noradrenergic system in the excessive grooming behavior induced by neuropeptide glutamic acid isoleucine

SÁNCHEZ M; ATTADEMO M; CELIS M.E

Nueva York, EEUU.

Congreso; Thirty-Fifth Annual Meeting, American Society for Neurochemistry; 2004

American Society for Neurochemistry

The neuropeptide glutamic acid isoleucine amide (NEI) inject into the intraventricularly (icv) induces excessive grooming behavior (EGB) and motor activity (MA). Previous data of our laboratory provides evidence that NEI utilizes not only the A-10 dopaminergic neurons to induces the behavior recently mentioned, but also the noradrenergic system to induce EGB and MA. Although noradrenergic terminals are poorly represented in these area, some authors postulated that a further ascending transmitter system modulating signal processing in the caudado putamen involves noradrenergic fibers originating in the locus coeruleus, so that it is likely that this neurotransmitter plays a role in the regulation of the MA. Male albino rats weighing 250-300g, housed and cared for at the Laboratory of Physiology were used. Here, we studied whether the noradrenergic system is involved in the NEI induced behavior. The present study demonstrated  that propranolol a general beta-adrenergic antagonist, injected icv previous to NEI, suppresses the behavior provoked by the icv injection of the peptide in a dose response manner. Metoprolol a beta1 adrenergic antagonist  blocked also these behavior. Whereas the prior icv injection of the phentolamine, an alpha-adrenergic antagonist, did not affect  at any  of the doses tested the EGB and MA induced by the peptide. These data support the hypothesis of a relationship between NEI and the noradrenergic system, and also, similar to other endogenous peptides, NEI could exert a neuromodulator effect in the central nervous system, contributing to the maintenance of the NA-Ach chemical balance in the striatum.