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Abstract #10598 Published in IGR 6-2
Evidence for Multiple P2Y Receptors in Trabecular Meshwork Cells
Crosson CE; Yates PW; Bhat AN; Mukhin YV; Husain SJournal of Pharmacology and Experimental Therapeutics 2004; 309: 484-489
The purpose of this study was to determine whether functional purinergic P2 receptors are present in trabecular meshwork cells. The human trabecular cell line HTM-3 and cultured bovine trabecular cells were used to assess the effects of P2 agonists on intracellular Ca2+ levels, extracellular signal-regulated kinase (ERK1/2) activation, and P2Y receptor expression. ATP, UTP, ADP, and 2-methyl-thio-adenosine triphosphate (2-MeS-ATP) each produced a concentration-dependent increase in intracellular Ca2+ in bovine trabecular cells and the HTM-3 cell line. The addition of UDP did not produce any detectable rise in intracellular Ca2+. Pretreatment with the P2Y1 receptor antagonist 2'-deoxy-N 6-methyladenosine-3',5'-diphosphate (MRS-2179) blocked the ADP- and 2-MeS-ATP-induced rise in intracellular Ca2+. However, the ATP- or UTP-induced rise in intracellular Ca2+ was not inhibited by MRS-2179 pretreatment. The addition of ADP, 2-MeS-ATP, ATP, or UTP were also found to activate the ERK1/2 signaling pathway. This activation of ERK1/2 was blocked by pretreatment with the mitogen-activated protein kinase kinase inhibitor 1,4-diamino-2,3-dicyano-1,4-bis(o-aminophenylmercapto)butadiene (U-0126) or the protein kinase C inhibitor chelerythrine chloride, but not by MRS-2179. Analysis of mRNA from HTM-3 cells by reverse transcription-polymerase chain reaction revealed the expression of P2Y1, P2Y4, and P2Y11 receptor subtypes. These data demonstrate that multiple P2Y receptors are present in trabecular cells. Our results are consistent with the idea that the mobilization of intracellular Ca2+ results from the activation of P2Y1 and P2Y4 receptors, whereas the activation of the ERK1/2 pathway results from the activation of P2Y4 receptors alone. However, a role for the P2Y11 receptors in mobilization of Ca2+, or activation of the ERK1/2 pathway, cannot be discounted.
Dr. C.E. Crosson, Storm Eye Institute, 167 Ashley Ave., Charleston, SC 29425
Classification:
2.5.1 Trabecular meshwork (Part of: 2 Anatomical structures in glaucoma > 2.5 Meshwork)
3 Laboratory methods
