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

In the present study, we investigated the effect of adenosine triphosphate (ATP) on cytosolic free calcium mobilization and mitogenic activity in cult ured bovine corneal endothelial cells (BCEC). The [Ca2+](i) was determined using a Ca2+ sensitive indicator, Fura-2/AM, and cell proliferation was eva luated 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-methylt hio-ATP > uridine triphosphate > ATP > adenosine diphosphate. Adenosine mon ophosphate and adenosine did not affect [Ca2+](i). ATP (10(-4) M) also prom oted the accumulation of inositol trisphosphate (IP3). The ATP-induced tran sient [Ca2+](i) increase and IP3 accumulation were attenuated by pretreatme nt with a phospholipase C inhibitor, U-73122 (5 mu M), 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 antago nist, suramin (10(-4) M). Thus, the present study indicates that BCEC conta in P2 purinoceptors that regulate their proliferation.