[Effects and activated mechanism of adenosine triphosphate on BK channel of coronary smooth muscle cells].
OBJECTIVE
To explore the effects and activation mechanism of adenosine triphosphate (ATP) on large conductance calcium-activated potassium channel ( BK channel) in coronary artery smooth muscle cells.


METHODS
Coronary smooth muscle cells were isolated by enzyme digestion from Sprague-Dawley rats. And BK currents were recorded by patch clamp technique in whole cell configuration. The effects of ATP on cytosolic calcium concentrations were examined by recording the changes of fluorescence intensity ratios.


RESULTS
BK current densities were (137 ± 13) pA/pF and (179 ± 15) pA/pF before and after a perfusion of 1 mmol/L ATP (P < 0.05). The fluorescence ratios were 2.46 ± 0.08 and 4.04 ± 0.21 (P < 0.05) before and after 0.5 mmol/L perfusion. After incubating with purine receptor (P2Y1) blocker MRS2179, phospholipase C (PLC) blocker U73122 and inositol triphosphate (IP3) blocker 2-APB, the fluorescence ratios were 2.7 ± 0.06, 2.65 ± 0.12 and 2.69 ± 0.13 respectively. Compared with control group, all fluorescence ratios decreased after incubating with three blockers (P < 0.05).


CONCLUSIONS
ATP may elevate intracellular calcium concentration via P2Y1-PLC-IP3 pathway consequently activating BK channel.
Wang
W
Xiangyun
Wu
W
Ying
Qian
Q
Lingling
Dang
D
Shipeng
Ji
J
Yuan
Xu
X
Feng
Wang
W
Meng
Tang
T
Xu
Yao
Y
Yong
Wang
W
Ruxing
D000255:Adenosine Triphosphate; D000818:Animals; D002118:Calcium; D003331:Coronary Vessels; D006321:Heart; D051036:Large-Conductance Calcium-Activated Potassium Channels; D009131:Muscle, Smooth, Vascular; D032389:Myocytes, Smooth Muscle; D018408:Patch-Clamp Techniques; D051381:Rats; D017207:Rats, Sprague-Dawley
D051036:Large-Conductance Calcium-Activated Potassium Channels; D000255:Adenosine Triphosphate; D002118:Calcium