Changes in Potassium Current and BK Channel Protein Expression in Coronary Artery Smooth Muscle Cells of Spontaneously Hypertensive Rats
Changes in Potassium Current and BK Channel Protein Expression in Coronary Artery Smooth Muscle Cells of Spontaneously Hypertensive Rats
Youlin Fu1, Zhongming Yang1 and Chongrong Qiu2*
ABSTRACT
The objective of this study was to analyze the changes of potassium current (PC) and large conductance calcium activated potassium channel (BK) protein expression in coronary artery (CA) smooth muscle cells of spontaneously hypertensive rats. Eight healthy male spontaneously hypertensive rats (hypertension group) and 8 normal rats (Wistar group) were selected, and CA smooth muscle cells were isolated from the two groups. The PC of CA smooth muscle cells were recorded by patch clamp whole cell recording technique, and the BK currents and BK tail currents of CA smooth muscle cells were recorded and compared between the two groups. The BK α and BK β proteins expression in the two groups was detected by western blot. The average PC density of CA smooth muscle cells in hypertension group decreased to (68.72±5.14) % after the addition of 100nM IBTX, while that in Wistar group reduced to (33.21±1.76) % after the addition of 100nM IBTX. When the PC of coronary smooth muscle cells of hypertensive rats was + 120mV, + 110mV, + 100mV and + 90mV, the current density after 3mm4-AP inhibition was strikingly higher than that of rats in Wistar group. The tail current of BK channel was recorded by 4-AP inhibition, and the current density of hypertensive rats was dramatically higher than that of rats in Wistar group. There was no significant difference in BK channel BK α protein expression between the two groups. The expression level of BK β protein in hypertension group of rats was markedly higher than that in Wistar group. The BK channel current and protein of CA smooth muscle cells in spontaneously hypertensive rats were significantly higher than those in normal rats, suggesting that the diastolic function of smooth muscle cells was enhanced, which is of great significance to the protection of coronary circulation in hypertension.
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