REGULATION OF THE PREFRONTAL CORTICAL DOPAMINE RELEASE BY GABA(A) AND GABA(B) RECEPTOR AGONISTS AND ANTAGONISTS

The gamma-aminobutyric acid-dopamine (GABA-DA) relationship was studied by intracerebral microdialysis in the prefrontal cortex. Nomifensine (5 muM) was included in the Ringer solution during all the dialysis experiments. Muscimol, a GABA(A) receptor agonist (50 and 500 muM) did not affect the extracellular output of DA and 3,4-dihydroxyphenylacetic acid (DOPAC). Baclofen, a GABA(B) receptor agonist (50 muM) significantly decreased the extracellular output of DA and DOPAC. On the other hand, picrotoxin and phaclofen, GABA(A) and GABA(B) receptor antagonists respectively, at a concentration of 50 muM, both significantly increased the release of DA. While the DOPAC level was affected only by picrotoxin perfusion. The present study indicates that GABA could control the release of DA in the prefrontal cortex.