Mechanisms underlying pathological oscillations in the rat 6- hydroxydopamine model of Parkinson?s disease

M.V. ESCANDE, C.L. ZOLD, L.A., POMATA P., RIQUELME, J.E. BELFORTE, M.G. MURER

Huerta Grande, Cordoba, Argentina

Congreso; II Reunión Conjunta de Neurociencias. Sociedad Argentina de Investigación en Neurociencias.; 2010

Patients with Parkinson?s disease and rats with nigrostriatal lesion induced by 6-hydroxydopamine (6-OHDA), a model of Parkinson?s disease, show enhanced basal ganglia oscillations in synchrony with cortical oscillations. The mechanisms underlying pathological oscillatory synchronization remain obscure. Recordings were performed in control rats and rats with nigrostriatal lesion under urethane anesthesia. In one set of experiments we explored the effect of blocking striatal NMDA receptors with the competitive antagonist AP-5 (100-200uM) on oscillatory activity in the external globus pallidus (GPe). In another set we studied the short latency (presumably monosynaptic) response of subthalamic (STN) neurons to cortical stimulation. GPe activity was not modified by intrastriatal AP-5 administration in control rats. However, the abnormal synchronization between GPe and cortical oscillations as estimated by coherence analysis, was reduced by 80% during intrastriatal AP-5 administration in rats with nigrostriatal lesion (p