The neural mechanism of apomorphine-induced erection: an experimental study by comparison with electrostimulation-induced erection in the rat model.

The rat model of an apomorphine (APO)-induced erection is accepted as a rapid, reproducible way of observing whether erectile capability is present. However there are still questions that can be asked about whether an APO erection shares the same neural pathway as a physiologic erection. We compared APO-induced erections of sham-operated rats with those in rats that had the hypogastric, pelvic and cavernous nerves ablated bilaterally. The results suggest that an APO-induced erection is a vascular event primarily mediated via the sacral parasympathetic nerve system and that, in case of injury to the parasympathetic nerve system, it may also be mediated by the thoracolumbar sympathetic pathway. Similarity in the neural pathways between APO-induced erection and a psychogenic erection makes this animal model useful for study of psychogenic erectile reflexes.