Penile reflexes in intact rats following anesthetization of the penis and ejaculation.

Application of the topical anesthetic pontocaine (tetracaine hydrochloride) to the penis and preputial sheath virtually abolished the display of penile reflexes by intact rats. When pontocaine was applied immediately following ejaculation in copula, however, normal genital reflexes were observed in the majority of rats, albeit with a prolonged latency to the first erection relative to the control test. These same animals were, nonetheless, unable to achieve intromission when returned to the mating arena despite repeated mounting attempts. These data suggest that sensory input to the genitalia is generally necessary for the display of penile reflexes in the rat. However, stimuli associated with copulation can override the suppressive effect of sensory loss of these reflexes, presumably due to removal of supraspinal inhibition.