[Experimental approach to reflex erection in rats: modeling and functional neuroanatomy of the involved nerve...

The neurophysiology of erection remains poorly elucidated, particularly at the spinal cord level. We studied variation of intracavernous pressure (ICP) in rats. Tactile stimulation of the prepuce in conscious rats induces the appearance of sequences of reflex erectile responses affecting the corpora cavernosa and/or corpus spongiosum and glans. During this test, implantation of a telemetric pressure transducer allowed us to record ICP increases occurring simultaneously to erectile responses. These increases were characterized by brief suprasystolic peaks preceded by an infrasystolic plateau. Each type of reflex erectile response was accompanied by a characteristic profile of ICP increase. Participation of the corpora cavernosa was demonstrated, particularly during erections of the glans. In anaesthetised rats, electrical stimulation of the dorsal nerve of the penis induces an increase of intracavernous pressure which tends to reach blood pressure values. This erectile response of the corpora cavernosa is abolished by proximal section of the dorsal nerve of the penis, markedly decreased by section of the homolateral pelvic nerve, and abolished after bilateral section of the two pelvic nerves. Striated muscle paralysis does not abolish the erectile response. These data help to define the neurophysiology of the reflex erection. In particular, they provide a clearer explanation of the spinal integration of reflex erection.