The Effects of Oral Administration of D-Modafinil on Male Rat Ejaculatory Behavior

Abstract

Premature ejaculation (PE) is one of the most common forms of male sexual dysfunction. Examination of various classes of drugs on ejaculation latency would provide further opportunities for drug development in this field. This study was conducted to examine the effects of the d-isomer of modafinil (d-modafinil) on ejaculatory behavior in a rat model. Male sexual behavior in the rat was examined after acute oral administration of d-modafinil (10 mg/kg, 30 mg/kg, and 100 mg/kg) in copulation studies with receptive females. The latency to ejaculation, post-ejaculatory interval, and the frequency of mounting behavior were measured. Results d-modafinil (30 mg/kg and 100 mg/kg) produced a significant delay in ejaculation. The delay in ejaculation was accompanied by an increase in the number of intromissions without any change in the mount or intromission latency. The possible mechanisms of action of d-modafinil to produce this delay in ejaculation are discussed. These results demonstrate that acute oral administration of d-modafinil can lengthen the latency to ejaculation in rats without suppressing sexual behavior. The greatest delay in ejaculation was observed in animals with shorter baseline ejaculatory latencies. Investigation into new classes of drugs that modulate ejaculation may provide new therapeutic options for treating.