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TRPV1‐dependent afferent nerve sensitivity is augmented during spontaneous phasic contractions in aged mouse urinary bladder
Author(s) -
Tykocki Nathan R.,
Heppner Thomas J.,
Nelson Mark T.
Publication year - 2013
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.27.1_supplement.lb868
Subject(s) - trpv1 , urinary bladder , capsaicin , isometric exercise , stimulation , endocrinology , medicine , contractility , afferent , electrophysiology , sensory nerve , urinary system , sensory system , chemistry , transient receptor potential channel , neuroscience , receptor , biology
TRPV1 channels in sensory nerves are thought to communicate bladder fullness to the central nervous system. The sense of bladder fullness (“urge”) increases with age. We hypothesized that TRPV1 activity is augmented in urinary bladders from aged mice. Bladders were isolated from 3‐ and 18‐month old C57BL6 male mice for isometric contractility or ex vivo afferent nerve activity recording during constant bladder filling (1.8 ml/hr). Electrical field stimulation caused significantly greater contractions (2‐fold at 50 Hz) in bladder strips from aged mice compared to young. Spontaneous phasic contractions (SPCs), measured as pressure increases during filling of isolated bladders, were not different in young and aged. SPCs elicited significant and transient increases in afferent nerve activity. TRPV1 channel inhibition with capsaicin (1 μM) caused a 23.5% greater reduction in afferent peak frequency and a 35.9% greater reduction in afferent area under the curve in aged versus young bladders. These data suggest that aging increases urinary bladder responsiveness to parasympathetic nerve stimulation and increases the contribution of TRPV1‐signaling to afferent nerve outflow. Supported by NIH R37‐DK053832.