Bladder functional disorders are common health problems; however, their pathologies are poorly understood. Adenosine triphosphate (ATP) released from the urothelium has been suggested to have an essential role in the micturition reflex, and its involvement in bladder functional disorders has been intensively investigated. Here, we review the latest advances in research on urothelial ATP signaling.
We reviewed research articles on the role of the urothelium and urothelial ATP release in bladder function.
Mice lacking purinergic receptors have been reported to exhibit marked bladder hyporeflexia. Based on this observation, it was commonly believed, according to the widely held ATP urothelial signaling theory, that stretch-induced urothelial ATP release mediates the sensation of bladder filling via purinergic receptors. However, recent studies employing novel experimental methods and approaches have demonstrated that there are no significant differences in bladder function between wild-type and purinergic receptor knockout mice under physiological conditions. Nonetheless, under pathological conditions, inhibition of purinergic receptors has been shown to improve bladder hyperactivity. Moreover, enhanced urothelial ATP release has been reported in patients with bladder functional disorders.
Recently, conflicting evidence has led us to question the role of urothelial ATP signaling in normal micturition reflex. In contrast, under pathological conditions, it seems likely that enhanced urothelial ATP signaling mediates bladder hyperactivity. These recent findings suggest that the urothelial ATP signaling pathway is a potential therapeutic target for bladder functional disorders.
Abstract AIMS: This is a pilot study to evaluate the feasibility of using diagnostic cardiac electrophysiology catheters for recording intrinsic urinary bladder electrical activity and for electrical pacing capture of bladder tissue. METHODS: During cystoscopy, a curved quadripolar catheter was introduced and contact was made with the right and left halves of the dome and trigone in adult female patients undergoing cystoscopy. Electrical activity was recorded, using a commercially available cardiac electrophysiologic recording system, before and during pacing at 0.5-3.0 Hz. RESULTS: Apparent spontaneous electrical depolarizations were detected in both the trigone and the dome. The amplitude of these depolarizations was in the microVolt range. During pacing, local electrical capture was noted in the trigone, but not in the dome. CONCLUSIONS: Spontaneous low-amplitude electrical activity was detected in the bladder through the use of commercially available cardiac electrophysiology equipment. While these low-level signals could represent noise, the voltage, and morphology resemble detrusor muscle action potentials previously seen in animal studies. Pacing induced local electrical capture in the trigone but not the dome.
PMID: 27494644 [PubMed - as supplied by publisher]
Hollander, J.B. Int Urol Nephrol (2016). doi:10.1007/s11255-016-1374-0
Urology - Book review
There is a great need in the world for skilled urologic practitioners. Urology physician extenders such as nurse practitioners, physician assistants and specialty trained medical assistants will be needed more and more in order to deliver timely and appropriate care to urologic patients. The office practice manual “The Nurse Practitioner in Urology” is now available and has the potential to become a main resource for office practice in urology. Written by urology nurse practitioners with over 32 years of urologic experience between them, the book serves as a guide for physician extenders in order to provide expert high quality cost effective care for adult urology patients. The book to me is so well written and practical that it may serve as a resource for office urologists themselves. The chapter highlights pertinent pathophysiology, assessment and diagnostics specific to GU conditions and promotes advanced critical thinking for physician extenders specializing in urology. The chapters are written with clinical pearls and practical resources that may be of value not only to physician extenders, but clinicians and patients themselves. In addition to standard outpatient management of both benign and malignant urological conditions, there are chapters on transitioning pediatric urology patients to adult environments, men’s health including low testosterone, erectile dysfunction and infertility, and newer concepts with regard to urinary retention and underactive bladder. The book emphasizes evidence based medicine and the resources necessary to practice in that fashion. The book is user friendly and easy to navigate. “The Nurse Practitioner in Urology” will be a valued asset to all mid-level providers, physician extenders and specialists in the office based practice in urology. I suspect it will be a valued asset to busy state-of-the-art urological offices.