P2x purinoceptor is not important in thymocyte apoptosis.

Since the P2X purinoceptor has been shown to be homologous with RP-2, a gene activated in thymocytes undergoing apoptosis after glucocorticoid treatment, we have investigated the possible role of P2X purinoceptors in thymocyte apoptosis. We report that P2X purinoceptor mRNA is expressed both in untreated rat thymocytes and thymocytes treated with the synthetic glucocorticoid, 6 alpha-methylprednisolone, in a dose that can induce apoptosis. Furthermore, the P2X receptor agonist, extracellular ATP, was unable to trigger apoptosis in rat thymocytes and had no effect on methylprednisolone-induced DNA fragmentation. Finally, the P2X purinoceptor antagonist, suramin and pyridoxalphosphate-6-azophenyl-2',4'-disulfonic acid, had no inhibitory effects on DNA fragmentation caused by methylprednisolone. Thus, our data demonstrate that P2X purinoceptors are not directly involved in glucocorticoid-mediated thymocyte apoptosis.