Reduced ³H-imipramine binding but unaltered ³H-serotonin uptake in platelets of adolescent enuretics

High affinity ³H-imipramine binding and ³H-serotonin uptake to platelets was evaluated in nine untreated adolescent enuretics (ages 13-18) and nine age- and sex-matched controls. A significant decrease in the maximal binding of ³H-imipramine (B_max) was observed in the enuretics as compared to the controls. No alteration in the affinity of ³H-imipramine to its binding sites (K_d) or in serotonin uptake kinetic parameters (V_max, K_m) was detected. The lack of correlation between B_max and V_max values might indicate that the binding sites for imipramine and the sites for serotonin uptake are not identical.