Seok Ho Cha1, Tae-Won Hahn2,*, Takashi Sekine1,
Kweon-Haeng Lee3 and Hitoshi Endou1
1Departmentﾊof Pharmacology and Toxicology, Kyorin University
School of Medicine, Mitaka, Tokyo 181-8611, Japan
2Departmentﾊof Ophthalmology, Catholic University Medical College,
Kangnam St.ﾊMary's Hospital,
505 Banpo-dong, Seocho-gu, Seoul 137-701, Korea
3Departmentﾊof Pharmacology, Catholic University Medical College,
505 Banpo-dong, Seocho-gu, Seoul 137-701, Korea
*ﾊ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ﾊM-10-3ﾊM) and the potency of agonists was ordered
as follows: 2-methylthio-ATPﾊ>ﾊuridine triphosphateﾊ>ﾊATPﾊ>ﾊadenosine
diphosphate. Adenosine monophosphate and adenosine did not affect [Ca2+]i.
ATP (10-4ﾊ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ﾊC inhibitor, U-73122 (5ﾊmM),
for 30ﾊmin. ATP (10-5ﾊM) significantly enhanced the proliferation
of BCEC. ATP-induced [Ca2+]i increase and cell proliferation
were inhibited by a purinoceptor antagonist, suramin (10-4ﾊM).
Thus, the present study indicates that BCEC contain P2 purinoceptors that
regulate their proliferation.
Keywords: Corneal endothelium, Adenosine triphosphate, Cytosolic free
calcium, Proliferation
Copyrightｩ The Japanese Pharmacological Society 2000
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