Seok Ho Cha1, Tae-Won Hahn2,*, Takashi Sekine1,
Kweon-Haeng Lee3 and Hitoshi Endou1
1Department╩of Pharmacology and Toxicology, Kyorin University School of Medicine, Mitaka, Tokyo 181-8611, Japan
2Department╩of Ophthalmology, Catholic University Medical College, Kangnam St.╩Mary's Hospital,
505 Banpo-dong, Seocho-gu, Seoul 137-701, Korea
3Department╩of Pharmacology, Catholic University Medical College, 505 Banpo-dong, Seocho-gu, Seoul 137-701, Korea
*╩To whom correspondence should be addressed.
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 trisphosphate (IP3). The ATP-induced transient [Ca2+]i increase and IP3 accumulation were attenuated by pretreatment with a phospholipase╩C inhibitor, U-73122 (5╩mM), 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.
Keywords: Corneal endothelium, Adenosine triphosphate, Cytosolic free calcium, Proliferation
Copyrightę The Japanese Pharmacological Society 2000
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