Detrusor myocyte activity and afferent signaling
1Wake Forest Institute for Regenerative Medicine, Wake Forest University School of Medicine, Winston-Salem, North Carolina 27157, USA. karl-erik.andersson@klinfarm.lu.se
Aims:
To discuss (1) mechanisms involved in the generation and control of myocyte contractions and consequent afferent nerve activity and (2) these mechanisms as targets for drugs aimed for treatment of overactive bladder (OAB) symptoms and detrusor overactivity (DO).
Methods:
Literature review of myocyte activation, bladder afferent nerves, mediators in the bladder, and translational aspects of the findings.
Results:
During bladder filling, there is normally no parasympathetic outflow from the spinal cord. Despite this, the bladder develops tone during filling and also exhibits non-synchronized local contractions and relaxations that are caused by a basal myogenic mechanical activity that may be reinforced by release of, for example, acetylcholine from non-neuronal and/or neuronal sources or local mediators, such as prostaglandins and endothelins. It is suggested that these spontaneous contractions are able to generate activity in afferent nerves ("afferent noise") that may contribute to DO and OAB.
Conclusions:
Spontaneous bladder myocyte contractions and factors that are able to modulate them, as well as the consequent afferent nerve activity, may be targets for drugs meant for treatment of OAB/DO.
More Related Videos
06:36A Decentralized (Ex Vivo) Murine Bladder Model with the Detrusor Muscle Removed for Direct Access to the Suburothelium during Bladder Filling
Published on: November 28, 2019
10:26Bladder Smooth Muscle Strip Contractility as a Method to Evaluate Lower Urinary Tract Pharmacology
Published on: August 18, 2014
Related Concept Videos
The Micturition Reflex
The process begins with bladder filling, where the bladder wall stretches as urine accumulates. This stretching activates the urine storage reflex, mediated by the sacral spinal segments and the pontine storage center. Efferent sympathetic impulses stimulate the detrusor muscle to relax and the internal urethral sphincter to contract, facilitating urine...
Anatomy of the Genitourinary System II: Bladder and Urethra
Parasympathetic Signaling
The effects of...
Urinary Bladder
In males, the bladder is situated in front of the rectum, while in females, it is positioned anterior to the vagina and uterus. The bladder floor contains an inverted triangular area called the trigone, defined by the two ureteric...
Relaxation of Skeletal Muscles
When an action potential reaches the axon terminal, it depolarizes the membrane and opens voltage-gated sodium channels. Sodium ions enter the cell, further depolarizing the presynaptic membrane. This depolarization causes voltage-gated calcium channels to open.
Smooth Muscle Contraction
The onset of contraction is triggered by an increase in calcium ions within the sarcoplasm, similar to the process in striated muscle. However, smooth muscles have a relatively smaller reservoir of the sarcoplasmic...
