INHIBITION OF A 5-HT3 RECEPTOR-MEDIATED CURRENT BY THE SELECTIVE SEROTONIN UPTAKE INHIBITOR, FLUOXETINE

The effect of the selective serotonin uptake inhibitor, fluoxetine, on the inward current mediated by 5-HT3 receptors was investigated with the whole-cell patch-clamp technique. Fluoxetine inhibited the peak 5- HT current with an IC50 value of 1.2 mu M. During continuous applicati on of fluoxetine at concentrations of less than or equal to 1 mu M, th ere was a transient decrease in the fluoxetine-induced inhibition of 5 -HT current. It is suggested that fluoxetine may have a short-lived ac tion on 5-HT current and that the 5-HT3 receptor is a possible acting site for the therapeutic use of fluoxetine.