EXTRACELLULAR DOPAMINE IN THE RAT VENTRAL TEGMENTAL AREA AND NUCLEUS-ACCUMBENS FOLLOWING VENTRAL TEGMENTAL INFUSION OF COCAINE

Rats were implanted with dual dialysis probes, one in the ventral tegm ental area, and another one ipsilateral in the nucleus accumbens. Infu sion of cocaine (10, 100, 1000 mM) into the ventral tegmental area gra dually increased extracellular dopamine to 164, 329 and 991% of baseli ne in the ventral tegmental area, but reduced dopamine to 76, 47 and 3 8% of baseline in the nucleus acumbens. These results are consistent w ith cocaine-induced feedback regulation of dopamine cell activity invo lving somatodendritic impulse-regulating dopamine D-2 autoreceptors.