비아그라에 대한 새로운 단계별 지도

Sexual stimulation that leads to an erection causes the manufacturing and release of nitric oxide during the penis. Nitric oxide results in an enzyme, guanylate cyclase, to generate cyclic guanosine monophosphate (cGMP) that is principally to blame for escalating and decreasing the scale of blood vessels carrying blood to and through the penis and