비아그라에 대한 사실 아무도 제안하지 않는다

Sexual stimulation that leads to an erection brings about the production and release of nitric oxide in the penis. Nitric oxide brings about an enzyme, guanylate cyclase, to provide cyclic guanosine monophosphate (cGMP) that may be mainly to blame for increasing and decreasing the dimensions of blood vessels carrying blood to and with the penis and