The firing rate of dopaminergic neurones in the ventral tegmental area of anaesthetised rats was dose-dependently (0.31-5.0 micrograms/kg i.v.) inhibited by the dopamine D3 receptor agonist, (+)-7-OH-DPAT (7-hydroxy-2-(di-n-propylamino)tetralin). The selective dopamine D3 receptor antagonist, (+)-S 14297 ((+)-[7-(N,N-dipropylamino)-5,6,7,8-tetrahydro-naphtho(2,3b)dihydro,2,3- furane]), dose-dependently (16-125 micrograms/kg i.v.) inhibited the action of (+)-7-OH-DPAT (5 micrograms/kg i.v.); its inactive distomer, (-)-S 17777 (125 micrograms/kg i.v.), was ineffective. Alone, (+)-S 14297 (125 micrograms/kg i.v.) did not modify the firing rate. Haloperidol (16 micrograms/kg i.v.) fully reversed the action of (+)-7-OH-DPAT and, alone, significantly increased firing rate. These data suggest that inhibitory (dendritic) dopamine D3 (auto)receptors control the electrical activity of ventral tegmental area-localised dopaminergic neurones.