title: Sex-dependent expression of TRPV1 in bladder arterioles.
abstract: Transient receptor potential vanilloid type 1 (TRPV1) is a major nociceptive ion channel implicated in bladder physiology and/or pathophysiology. However, the precise expression of TRPV1 in neuronal vs. nonneuronal bladder cells is uncertain. Here we used reporter mouse lines (TRPV1-Cre:tdTomato and TRPV1PLAP-nlacZ) to map expression of TRPV1 in postnatal bladder. TRPV1 was not detected in the urothelium, however, we found marked expression of TRPV1 lineage in sensory nerves, and surprisingly, in arterial/arteriolar smooth muscle (ASM) cells. Tomato fluorescence was prominent in the vesical arteries and in small-diameter (15-40 μm) arterioles located in the suburothelial layer with a near equal distribution in bladder dome and base. Notably, arteriolar TRPV1 expression was greater in females than in males and increased in both sexes after 90 days of age, suggesting sex hormone and age dependency. Analysis of whole bladder and vesical artery TRPV1 mRNA revealed a similar sex and developmental dependence. Pharmacological experiments confirmed functional TRPV1 protein expression; capsaicin increased intracellular Ca2+in ∼15% of ASM cells from wild-type female bladders, but we observed no responses to capsaicin in bladder arterioles isolated from TRPV1-null mice. Furthermore, capsaicin triggered arteriole constriction that was rapidly reversed by the TRPV1 antagonist, BCTC. These data show that predominantly in postpubertal female mice, bladder ASM cells express functional TRPV1 channels that may act to constrict arterioles. TRPV1 may therefore play an important role in regulating the microcirculation of the female bladder, and this effect may be of significance during inflammatory conditions.
authors.affiliation: Department of Pharmacology & Physiology, Georgetown University, Washington, DC.|Department of Biology, Vinh University, Vinh City, Vietnam; and.
authors.forename: Thieu X
authors.initials: TX
authors.lastname: Phan
authors.affiliation: Department of Pharmacology & Physiology, Georgetown University, Washington, DC.|Department of Biology, Vinh University, Vinh City, Vietnam; and.
authors.forename: Hoai T
authors.initials: HT
authors.lastname: Ton
authors.affiliation: Department of Pharmacology & Physiology, Georgetown University, Washington, DC.
authors.forename: Yue
authors.initials: Y
authors.lastname: Chen
authors.affiliation: Department of Biomedical Sciences, West Virginia School of Osteopathic Medicine, Lewisburg, West Virginia.
authors.forename: Maureen E
authors.initials: ME
authors.lastname: Basha
authors.affiliation: Department of Pharmacology & Physiology, Georgetown University, Washington, DC; gpa3@georgetown.edu.
authors.forename: Gerard P
authors.initials: GP
authors.lastname: Ahern
mesh_terms: D000818:Animals; D001160:Arterioles / Q000187:drug effects / Q000378:metabolism*; D002211:Capsaicin / Q000494:pharmacology; D005260:Female; D008297:Male; D051379:Mice; D009131:Muscle, Smooth, Vascular / Q000187:drug effects / Q000378:metabolism; D012727:Sex Characteristics; D050916:TRPV Cation Channels / Q000235:genetics / Q000378:metabolism*; D001743:Urinary Bladder / Q000098:blood supply* / Q000187:drug effects / Q000378:metabolism
chemical_list: D050916:TRPV Cation Channels; C493921:TRPV1 protein, mouse; D002211:Capsaicin
keywords: TRPV1; arterioles; bladder; vasculature