Alfuzosin improves penile erection triggered by apomorphine in spontaneous hypertensive rats

Growing evidence suggest that BPH is a risk factor for ED. Since alfuzosin is a cornerstone in the treatment of BPH patients, we assessed the effect of alfuzosin on erectile function in rats when combined with a pro-erectile drug such as apomorphine.

Potencies of alfuzosin, apomorphine or the combination to relax norepinephrine (NE) precontracted corpus cavernosum tissue of spontaneous hypertensive rats (SHR) were determined. In anaesthetized rats, intracavernous and blood pressures were recorded after administration of apomorphine (10-250microg/kg s.c.) and alfuzosin (3-30microg/kg i.v.).

Alfuzosin fully relaxed the NE-precontracted penile tissue (pIC(50)=6.62+/-0.7) while apomorphine, up to 10microM, did not produce any relaxation. The potency of alfuzosin to relax erectile tissue was not further enhanced with 10microM apomorphine. Apomorphine induced erections in rat while alfuzosin alone did not. However, alfuzosin (30microg/kg) significantly enhanced the potency of apomorphine, to induce erections (ED(50)=25microg/kg versus 57microg/kg). In addition, alfuzosin even at 3microg/kg, significantly increased the intracavernous pressure (ICP) during erectile events up to 52-55mmHg when compared to ICP values of 29mmHg with 50microg/kg apomorphine alone.

These results show that alfuzosin enhances the number and amplitude of erections induced by apomorphine in SHR. Therefore, clinical evaluation of alfuzosin in association with apomorphine is warranted.