Communications biologyJul 14, 2026

Daily rhythms affect bladder capacity and tissue structure changes independently of behavior controlled by the brain’s central clock

Circadian Biology Weekly Brief ↗PubMed ↗DOI ↗OA ↗

Updated Jul 15, 2026

Abstract

Bmal1 conditional knockout mice retained circadian variation in bladder capacity despite losing behavioral rhythmicity.

Mammals have a natural rhythm in bladder capacity that may not rely solely on the brain's central clock.
Knockout mice exhibited a significant diurnal pattern in bladder capacity even in constant darkness.
Circadian changes in bladder capacity were linked to the expression of bladder clock genes.
Transcriptomic analyses revealed daily variations in bladder-related factors associated with extracellular matrix.
These findings suggest that the bladder may have its own circadian mechanisms influencing its capacity.

Simplified

Mammals exhibit a circadian rhythm of bladder capacity, but whether this rhythm can be maintained through intrinsic bladder mechanisms independently of central clock-driven behavioral rhythms remains unclear. Here, we addressed this question using Bmal1 conditional knockout mice lacking central clock function in the brain. Under constant darkness, these mice lost behavioral rhythmicity but largely retained circadian variation in bladder capacity together with bladder clock gene expression. Transcriptomic analyses further identified diurnal variation in bladder extracellular matrix-related factors, suggesting a potential molecular basis for bladder capacity rhythmicity. These findings indicate that the bladder harbors a peripheral circadian mechanism that contributes to the circadian regulation of bladder capacity and provides insight into the role of peripheral clock mechanisms in bladder pathophysiology.