[Effects of potassium channel blockers on the proliferation of rat bronchial smooth muscle cells].
OBJECTIVE
To investigate the effects of blockers of the three kinds of potassium channels: voltage-dependent K+ channel(KV), calcium-activated K+ channel(KCa) and ATP-sensitive K+ channel(KATP), on the proliferation of rat bronchial smooth muscle cells (BSMCs).


METHODS
The effects of three kinds of potassium channel blockers on the proliferation of BSMCs were detected by MTT method, immunocytochemistry staining and flow-cytometry. Their effects on the dynamic changes of Ca2+ concentration in BSMCs were investigated by the fluorophotometry of Fura-2/AM.


RESULTS
The KV blocker 4-aminopyridine (4-AP) was shown to significantly increase the expression of proliferating cell nucleus antigen in cultured rat BSMCs (P < 0.01), but the KCa blocker tetraethylammonium (TEA) and KATP blocker glibenclamide(Glib) did not show such effect (P > 0.05). 4-AP was found to significantly increase the optical density value of the cultured BSMCs (P < 0.01) by MTT method and the numbers of S + G2M BSMCs(P < 0.05) by flow-cytometry. TEA and Glib did not show such effects. 4-AP significantly increased the Ca2+ concentration in cultured BSMCs(P < 0.01). TEA and Glib did not show such effects.


CONCLUSIONS
This result suggests that inhibition of KV activity can increase intracellular Ca2+ and proliferation of rat BSMCs, but inhibition of KCa and KATP showed no effect.
Liu
Xian-sheng
XS
Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China. liuxiansheng@tjh.tjmu.edu.cn
Xu
Yong-jian
YJ
Zhang
Zhen-xiang
ZX
Ni
Wang
W
D015761:4-Aminopyridine / Q000494:pharmacology*; D000818:Animals; D001980:Bronchi / Q000166:cytology*; D002118:Calcium / Q000378:metabolism; D002455:Cell Division / Q000187:drug effects; D002478:Cells, Cultured; D005905:Glyburide / Q000494:pharmacology; D009130:Muscle, Smooth / Q000187:drug effects* / Q000378:metabolism; D026902:Potassium Channel Blockers / Q000494:pharmacology*; D024681:Potassium Channels, Calcium-Activated / Q000037:antagonists & inhibitors; D024642:Potassium Channels, Voltage-Gated / Q000037:antagonists & inhibitors; D018809:Proliferating Cell Nuclear Antigen / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D019789:Tetraethylammonium / Q000494:pharmacology
D026902:Potassium Channel Blockers; D024681:Potassium Channels, Calcium-Activated; D024642:Potassium Channels, Voltage-Gated; D018809:Proliferating Cell Nuclear Antigen; D019789:Tetraethylammonium; D015761:4-Aminopyridine; D005905:Glyburide; D002118:Calcium