ACCUMBENS MICROINJECTION OF LY-171555 AND SULPIRIDE - EFFECTS ON CIRCLING BEHAVIOR, IN THE RAT

In rats with unilateral 6-hydroxydopamine lesions of the substantia ni gra (pars compacta) and amphetamine i.p. some parameters of the rotati onal activity, following intra-accumbens microinjection of D-2 agonist (LY 171555) and antagonist (sulpiride), have been analyzed. An increa se in the number of turns was observed with LY 171555, whereas sulpiri de determined a decrease. The type of circling was also analyzed: D-2 agonist induced a very close turn around the central axis of the anima l and D-2 antagonist a close turn in the centre of the cage. Data were compared with control condition, which exhibited a large turn around the walls of the cage. The results show that pharmacological manipulat ion of nucleus accumbens influences rotational behaviour with a specif ic role for D-2 receptors.