Changes in penile sensitivity following papaverine-induced erection in sexually functional and dysfunctional men

To understand more clearly the role of penile sensitivity in sexual functioning, changes in penile thresholds resulting from papaverine-induced tumescence were studied in men who were either sexually functional or suffering from erectile dysfunction. Variable vibratory tactile stimulation was applied to 2 different sites, the base and tip of the underside of the penis. With standard psychophysical methodology, subjective thresholds were determined from a minimum of 5 threshold crossings. Results indicated a significant elevation in threshold after intracavernous papaverine injection, even though only partial erection was induced in most subjects. Men with erectile dysfunction had higher thresholds than control subjects but no difference in sensitivity was found between the base and tip of the penis. These findings indicate that low penile sensitivity is characteristic of some, although not all, men experiencing erectile problems and that this sensitivity is even lower during tumescence.