[Effects of iptakalim on the proliferation of cultured rabbit pulmonary arterial smooth muscle cells induced by endothelin-1].

OBJECTIVE: To explore the effects of iptakalim on the proliferation of rabbit pulmonary arterial smooth muscle cell(PASMC) induced by endothelin-1(ET-1) in vitro. METHODS: The experimental models of proliferation of rabbit PASMC induced by ET-1 in vitro were established and [(3)H]-thymidine ([(3)H]-TdR) incorporation and flow cytometric analysis(FCA) were used. RESULTS: The value of [(3)H]-TdR incorporation in ET-1 group was increased 1.468 times higher than that in control group. Iptakalim at the concentrations of 10(-7) mol/L, 10(-6) mol/L, 10(-5) mol/L lowered [(3)H]-TdR incorporation by (19.8 +/- 4.6)%,(41.2 +/- 9.5)%, (54.7 +/- 10.1)%, declined the total of the DNA synthesis (S) and the mitotic phase (G(2)/M) ratios by (36.6 +/- 5.7)%, (42.6 +/- 4.9)%, (66.3 +/- 4.7)%, and increased the static phase (G(0)/G(1)) ratio by (14.4 +/- 3.0)%, (17.9 +/- 2.6)%, (27.9 +/- 3.2)%, respectively, compared with the value of the cells treated with ET-1 only (P < 0.01). Glibenclimide abolished the effect of iptakalim on [(3)H]-TdR incorporation. CONCLUSION: Iptakalim has an inhibitory effect on PASMC proliferation induced by ET-1 through activating ATP sensitive potassium (K(ATP)) channels.