Internal urethral sphincter (smooth muscle component of the urethra) (IUS)

"Urethral smooth muscle" refers primarily to the **internal urethral sphincter**, which is composed of smooth muscle fibers located at the junction between the bladder and proximal urethra. This structure is responsible for involuntary control over urine outflow and plays a crucial role in maintaining urinary continence. The internal sphincter is under autonomic nervous system regulation—sympathetic stimulation maintains tonic contraction to prevent leakage, while parasympathetic activity promotes relaxation during urination. Dysfunction or incompetence of this smooth muscle can contribute to conditions such as urinary incontinence[1][7]. However, "urethral smooth muscle" does not refer to a specific molecular entity like an enzyme or receptor but rather describes a tissue type made up of many cells and proteins. **Note:** This entry is considered *incorrect* as a therapeutic target because "urethral smooth muscle" is not itself a discrete molecular target suitable for direct pharmacological intervention; it represents an anatomical structure composed mainly of contractile cells rather than being defined by one specific protein or receptor[1][3]. For structured drug discovery purposes, more precise targets would be individual receptors or ion channels expressed within these muscles.

Other names

Urethral smooth muscleinternal sphincterinternal urethral sphincter muscle