Cavernosal vascular and trabecular smooth muscle

Cavernosal vascular and trabecular smooth muscle forms the core structural and functional component within the corpora cavernosa of the penis, consisting of interwoven smooth muscle cells in trabeculae that surround endothelial-lined sinusoids and lacunar spaces. During sexual arousal, parasympathetic stimulation triggers nitric oxide (NO) release from endothelial and neuronal sources, leading to smooth muscle relaxation, helicine artery dilation, and blood influx that expands the sinusoids, compresses subtunical venules against the tunica albuginea, and traps blood to produce a rigid erection via veno-occlusion. This muscle is supported by intracavernosal pillars and the bilayered tunica albuginea, with skeletal muscles like the ischiocavernosus and bulbospongiosus contributing to rigidity and venous compression. In disease, dysfunction arises from impaired relaxation due to endothelial damage, reduced NO synthase activity, or conditions like diabetes, hypertension, and atherosclerosis, resulting in erectile dysfunction (ED), the inability to achieve or sustain erection. Therapeutically, PDE5 inhibitors such as sildenafil enhance cGMP signaling downstream of NO to restore relaxation, making this smooth muscle a key target for ED pharmacotherapy, though challenges include off-target vasodilation effects.

Other names

Corpus cavernosum smooth muscleCavernosal smooth muscleTrabecular smooth muscle

PDE5 inhibition increases cGMP to promote smooth muscle relaxation and NO-mediated vasodilation NO-mediated relaxation of smooth muscle via endothelial and neuronal NOS