Related Experiment Video
Updated: Aug 22, 2026

Application of Genetically Encoded Fluorescent Nitric Oxide (NO•) Probes, the geNOps, for Real-time Imaging of NO• Signals in Single Cells
Published on: March 16, 2017
Physiologic role of nitric oxide and nitric oxide synthase in female lower urinary tract
Mat H Ho1, Narender N Bhatia, Omid Khorram
1Department of Obstetrics and Gynecology, Harbor-UCLA Medical Center, David Geffen School of Medicine, University of California, Los Angeles, California, USA. mho@obgyn.humc.edu
Purpose Of Review:
In recent years nitric oxide (NO) has gained increasing recognition as an important neurotransmitter and cell signaling molecule with a broad range of functions in the lower urinary tract. This review discusses recently published data related to the physiologic and pathophysiologic roles of NO and nitric oxide synthase (NOS) in the female lower urinary tract.
Recent Findings:
Expression of three isoforms of NOS, namely endothelial NOS, neuronal NOS and inducible NOS, has been identified in various tissues of the lower urinary tract in animals and humans. In addition to its relaxation effects on bladder and urethra, NO also serves as a neurotransmitter in the lower urinary tract. The physiologic roles of NO in overactive bladder, bladder outlet obstruction, diabetic cystopathy, interstitial cystitis, and bladder inflammation have been demonstrated.
Summary:
NO plays an important role in the micturition process and in disorders of the lower urinary tract. Improved understanding of the pathophysiologic role of NO/NOS system and of the L-arginine-NO-cGMP pathway may allow us to identify suitable therapeutic targets for lower urinary tract disorders. However, there is a need for further investigation to determine the precise function of NO in human lower urinary tract because most work thus far has been done in animal models.
Related Concept Videos
Nitric Oxide Signaling Pathway
Microbiota of the Urogenital Tract
Anatomy of the Genitourinary System II: Bladder and Urethra
Antihypertensive Drugs: Vasodilators
Urethra
The anatomy of the urethra differs between males and females. In females, the urethra is short, measuring about 3–4 cm in length, and opens anterior to the vaginal opening. In males, the urethra is longer and passes through the penis, serving dual purposes: expelling urine and ejaculating semen. The male urethra is...
Physiology of the Genitourinary System III: Urine Concentration and Dilution

