Expression and function of rat urothelial P2Y receptors.
The control and regulation of the lower urinary tract are partly mediated by purinergic signaling. This study investigated the distribution and function of P2Y receptors in the rat urinary bladder. Application of P2Y agonists to rat urothelial cells evoked increases in intracellular calcium; the rank order of agonist potency (pEC(50) +/- SE) was ATP (5.10 +/- 0.07) > UTP (4.91 +/- 0.14) > UTPgammaS (4.61 +/- 0.16) = ATPgammaS (4.70 +/- 0.05) > 2-methylthio adenosine 5'-diphosphate = 5'-(N-ethylcarboxamido)adenosine = ADP (<3.5). The rank order potency for these agonists indicates that urothelial cells functionally express P2Y(2)/P2Y(4) receptors, with a relative lack of contribution from other P2Y or adenosine receptors. Real-time PCR, Western blotting, and immunocytochemistry confirmed the expression of P2Y(2) and to a lesser extent P2Y(4) in the urothelium. Immunocytochemical studies revealed expression of P2Y(2) staining in all layers of the urothelium, with relative absence of P2Y(4). P2Y(2) staining was also present in suburothelial nerve bundles and underlying detrusor smooth muscle. Addition of UTP and UTPgammaS was found to evoke ATP release from cultured rat urothelial cells. These findings indicate that cultured rat urothelial cells functionally express P2Y(2)/P2Y(4) receptors. Activation of these receptors could have a role in autocrine and paracrine signaling throughout the urothelium. This could lead to the release of bioactive mediators such as additional ATP, nitric oxide, and acetylcholine, which can modulate the micturition reflex by acting on suburothelial myofibroblasts and/or pelvic afferent fibers.
Chopra
Bikramjit
B
A1207 Scaife Hall, Dept. of Medicine, Univ. of Pittsburgh, 3550 Terrace St., Pittsburgh, PA 15261, USA.
Gever
Joel
J
Barrick
Stacey R
SR
Hanna-Mitchell
Ann T
AT
Beckel
Jonathan M
JM
Ford
Anthony P D W
AP
Birder
Lori A
LA
D000255:Adenosine Triphosphate / Q000494:pharmacology; D000818:Animals; D002118:Calcium / Q000502:physiology; D002478:Cells, Cultured; D017931:DNA Primers; D005786:Gene Expression Regulation; D007150:Immunohistochemistry; D016133:Polymerase Chain Reaction; D051381:Rats; D017207:Rats, Sprague-Dawley; D018048:Receptors, Purinergic P2 / Q000235:genetics*; D058473:Receptors, Purinergic P2Y2; D001743:Urinary Bladder / Q000166:cytology / Q000187:drug effects / Q000502:physiology*; D019459:Urothelium / Q000166:cytology / Q000187:drug effects / Q000502:physiology*
D017931:DNA Primers; C546387:P2ry2 protein, rat; D018048:Receptors, Purinergic P2; D058473:Receptors, Purinergic P2Y2; C104749:purinoceptor P2Y4; D000255:Adenosine Triphosphate; D002118:Calcium