Figure 6. The corpus cavernosum SMCs, which are poised between contraction and relaxation, are controlled by multiple stimuli released from neurons, endothelial cells and the interstitial cells of Cajal.

Some of the stimuli such as noradrenaline (NA) and prostaglandin F_2α (PGF_2α) drive contraction, whereas nitric oxide (NO), prostaglandin E₂ (PGE₂) and vasoactive intestinal peptide (VIP) control relaxation. See text for details of their signalling pathways. Reproduced from Berridge (2008), with permission.