비아그라에 대해 거의 알려지지 않은 사실

Sexual stimulation that results in an erection triggers the creation and release of nitric oxide inside the penis. Nitric oxide leads to an enzyme, guanylate cyclase, to provide cyclic guanosine monophosphate (cGMP) which is mainly liable for increasing and lowering the dimensions of blood vessels carrying blood to and in the penis and causing an e