The excitation process of the smooth muscle of corpus cavernosum is important to the erectile process. single-cell electrophysiology performed during the last decade has given deep insights into the different current components participating in that process. However, the existence of a tremendous amount of literature might be confusing for the nonspecialist in the field of smooth-muscle excitation and, especially, in the excitation of corpus cavernosum. In a compact form, this paper gives an overview on significant ionic currents as well as their ability to change the membrane potential and to enhance or inhibit calcium influx for the modulation of smooth-muscle tone.