Urothelium update: how the bladder mucosa measures bladder filling

Area of Science:

• Urology
• Cell Biology
• Neuroscience

Background:

• The bladder urothelium plays a crucial role in sensing bladder filling through various mechanoreceptors and signaling pathways.
• Continuous adaptation of urothelial barrier and afferent signaling functions is necessary to manage bladder wall stretch and urine exposure.

Purpose of the Study:

• To critically evaluate the existing evidence on mechanoreceptors and pathways involved in normal bladder filling signaling.
• To discuss potential novel receptors and pathways that may contribute to bladder filling sensation.

Main Methods:

• Review of in vitro and in vivo studies examining signaling pathways (e.g., adenosine triphosphate, cholinergic, nitric oxide, adrenergic).
• Evaluation of urothelial receptors including purinergic receptors, sodium channels, and transient receptor potential (TRP) channels.
• Discussion of other relevant pathways and receptors implicated in bladder filling.

Main Results:

• Intracellular calcium ion increase is a key factor in bladder filling signaling.
• The bladder mucosa contains essential pathways and receptors mediating bladder filling.
• A comprehensive understanding of how interacting pathways and receptors generate bladder filling signals is still lacking.

Conclusions:

• Normal bladder filling sensation is orchestrated by multiple interacting mechanoreceptors and signaling pathways.
• Future research should prioritize elucidating the intricate interactions between these components to fully comprehend normal bladder filling signaling.