[Behavioral changes following lesioning of the nucleus accumbens (ACB) and effects of centrally acting drugs in rats (author's transl)].

ACB is one of the sites containing nerve terminals of the mesolimbic dopamine system. We have found that all the male Sprague-Dawley rats with electrolytic lesions of bilateral ACB showed locomotor hyperactivity and hyperemotionality. Muricide was also observed in about 40% of these lesioned rats. Hyperemotionality and muricide were maximum during the first 2-3 days after the lesioning, then gradually declined. Locomotor hyperactivity lasted invariably for over 30 days. Hyperemotionality and muricide were both inhibited by the following drugs given i.p., chlorpromazine; haloperidol; diazepam; estazolam; aminooxyacetic acid (GABA transaminase inhibitor); phenoxybenzamine. However, imipramine, atropine and L-5-hydroxytryptophan inhibited selectively the muricidal behavior. Lesioning of the catecholaminergic (CA) system by administration of 6-hydroxydopamine into bilateral ACB-produced only moderate hyperemotionality with no evidence of locomotor hyperactivity and muricide. These results suggest that lesioning of the CA system plus other neural mechanisms in ACB are required for development of these three forms off hyperemotional behavior. Cholinergic, serotonergic, GABAergic and CA mechanisms may also be involved in hyperemotionality and muricide in ACB lesioned rats.