비아그라에 대한 5가지 쉬운 사실 설명

Sexual stimulation that causes an erection brings about the production and launch of nitric oxide during the penis. Nitric oxide leads to an enzyme, guanylate cyclase, to make cyclic guanosine monophosphate (cGMP) that may be mostly accountable for rising and lowering the dimensions of blood vessels carrying blood to and through the penis and produ