Purinoceptor-mediated calcium mobilization and cellular proliferation in cultured bovine corneal endothelial cells

Abstract

In the present study, we investigated the effect of adenosine triphosphate (ATP) on cytosolic free calcium mobilization and mitogenic activity in cultured bovine corneal endothelial cells (BCEC). The [Ca2+](i) was determined using a Ca2+ sensitive indicator, Fura-2/AM, and cell proliferation was evaluated by counting the cell number. ATP, its metabolites and analogs caused transient increase in [Ca2+](i) in a concentration-dependent manner (10-7 M - 10-3 M) and the potency of agonists was ordered as follows: 2-methylthio-ATP > uridine triphosphate > ATP > adenosine diphosphate. Adenosine monophosphate and adenosine did not affect [Ca2+](i). ATP (10-4 M) also promoted the accumulation of inositol triphosphate (IP3). The ATP-induced transient [Ca2+](i) increase and IP3 accumulation were attenuated by pretreatment with a phospholipase C inhibitor, U-73122 (5 μM), for 30 min. ATP (10-5 M) significantly enhanced the proliferation of BCEC. ATP-induced [Ca2+](i) increase and cell proliferation were inhibited by a purinoceptor antagonist, suramin (10-4 M). Thus, the present study indicates that BCEC contain P2 purinoceptors that regulate their proliferation.