EFFECT OF EXTRACELLULAR ADENOSINE 5'-TRIPHOSPHATE ON PRINCIPAL NEURONS OF THE RAT VENTRAL TEGMENTAL AREA

Intracellular recordings were made in a midbrain slice preparation of the rat brain containing the ventral tegmental area (VTA). Dopaminergi c principal cells were identified by their electrophysiological proper ties and their hyperpolarizing responses to dopamine. Superfusion with dopamine (100 mu M) caused hyperpolarization and a decrease of the ap parent input resistance. By contrast, two structural analogues of ATP, 2-methylthio ATP (2-MeSATP; 10 mu M) and alpha,beta-methylene ATP (al pha,beta-meATP; 30 mu M) had no effect, when added to the superfusion medium. Pressure applied dopamine also hyperpolarized the membrane, wh ile both 2-MeSATP and alpha,beta-meATP were ineffective. Hence, dopami nergic principal neurons of the VTA do not possess somatic P2 purinoce ptors present on peripheral and central noradrenergic neurons. (C) 199 8 Elsevier Science B.V. All rights reserved.