Time course of the effect of paroxetine (0.8 mg kg−1 i.v.) on 5-HT levels in dialysates of the frontal cortex in vehicle- and (±)-pindolol (4 mg kg−1) pretreated animals. The vehicle was acetic acid/glucose. Drugs were given as indicated by the arrows. Basal levels of 5-HT were 11±2 (5), 25±5 (4), 15±2 (6) and 23±5 (6) fmol sample−1, in the groups of animals which received vehicle/vehicle, (±)-pindolol/vehicle, vehicle/paroxetine and (±)-pindolol/paroxetine, respectively.