Effect of beta noradrenergic receptors in the behavior induced by neuropeptide glutamic acid isoleucine amide

SÁNCHEZ M; ATTADEMO M; CELIS M.E

Pinamar, Buenos Aires,

Congreso; XX Reunion Anual de la Sociedad Argentina de Neuroquimica; 2005

Sociedad Argentina de Neuroquímica

The neuropeptide glutamic acid isoleucine amide (NEI) injected intracerebroventricular (icv) induced excessive grooming behavior (EGB) and motor activity (MA) through A-10 dopaminergic neurons as wells as the noradrenergic system. We studied whether the last system is involved in the NEI induced these behaviors. Male Wistar rats weighing 250-300g were used. The rats were icv implanted. The resulted shown that any of the adrenergic antagonist per se in the doses used affect EGB and MA. Propranolol, a general beta  adrenergic antagonist, injected icv previous to NEI, suppresses the behavior provoked by the peptide in a dose response manner. Metoprolol, a beta1 adrenergic antagonist, blocked also these behaviors. Whereas the prior icv injection of phentolamine, an alpha adrenergic antagonist, as well as ICI 118.55, a beta2 adrenergic antagonist, did not affect at any of the doses tested the studied behaviors induced by NEI. On the other hand, isoproterenol, a general beta agonist, as well as dobutamine, a beta1 agonist, behaved very similar to NEI. These data support the hypothesis of a relationship between NEI and the beta noradrenergic receptor, being specifically the beta1 receptor and similar to other endogenous peptides as neurotensin, cholecytokinin, substance P and alpha-MSH; NEI could exert a neuromodulator effect in the CNS.