Immunohistochemical evidence of vanilloid receptor 1 in normal human urinary bladder.
OBJECTIVE
Experimental and clinical evidences have shown the importance of the vanilloid receptor 1 (TRPV1) in the lower urinary tract. In humans, this receptor has been detected in nerve endings of primary sensory neurons, smooth muscle and connective tissue cells and in the rat also in the urothelium. The aim of this study is to identify, by immunohistochemistry, the cell types expressing TRPV1 in the human urinary bladder.


METHODS
Specimens, obtained from normal urinary bladder by multiple biopsy and from ureter at the time of radical nefrectomy for renal cell carcinoma, were fixed and frozen. Full-thickness sections were processed for light and fluorescence microscopes. To label the TRPV1, three polyclonal antibodies were used: the anti-capsaicin receptor, the anti-VR1 (N-15) and the anti-VR1 (C-15).


RESULTS
Urothelium, smooth muscle cells, mast cells and endothelium were labelled and the labelling was intracytoplasmatic. In the urothelial cells, the labelling was slightly granular. In the bladder urothelium, the superficial cells were more intensely stained than the basal and club-shaped cells. VR1-positive nerve fibers were seen running single and/or in groups in the sub-urothelium and as single varicose fibers in the muscle coat, and VR1-positive nerve endings in the urothelium.


CONCLUSIONS
The present findings provide the evidence of the presence of TRPV1 on normal human urothelium where it could have important implications in the mechanism of action of intravesical vanilloids (capsaicin and resiniferatoxin).
Lazzeri
Massimo
M
Department of Urology, University of Ferrara, Via Savonarola 4, Ferrara, Italy. lazeri.m@tiscali.it
Vannucchi
Maria Giuliana
MG
Zardo
Claudio
C
Spinelli
Michele
M
Beneforti
Patrizia
P
Turini
Damiano
D
Faussone-Pellegrini
Maria-Simonetta
MS
D006801:Humans; D007150:Immunohistochemistry; D011955:Receptors, Drug / Q000032:analysis*; D050916:TRPV Cation Channels; D001743:Urinary Bladder / Q000737:chemistry*
D011955:Receptors, Drug; D050916:TRPV Cation Channels; C494484:TRPV1 receptor