비아그라에 대한 5가지 쉬운 사실 설명

Sexual stimulation that causes an erection results in the production and release of nitric oxide from the penis. Nitric oxide results in an enzyme, guanylate cyclase, to provide cyclic guanosine monophosphate (cGMP) that's principally answerable for growing and lowering the dimensions of blood vessels carrying blood to and in the penis and leading