2-APB对自发性高血压大鼠脑微动脉平滑肌细胞缝隙连接的影响

为探讨正常血压Wistar大鼠(Wistar rat,WR)和自发性高血压大鼠(Spontaneously Hypertensive rat,SHR)脑微动脉段平滑肌细胞电生理学及偶联力的异同,并观察2-氨基乙基二苯硼酸酯(2-Aminoethoxydiphenyl borate,2-APB)对脑微动脉平滑肌细胞间缝隙连接的影响。应用全细胞膜片钳技术方法,观察2-APB对WR和SHR脑微动脉段上平滑肌细胞膜电容(Cinput)、膜电导(Ginput)和膜电阻(Rinput)的影响。结果显示,(1)SHR收缩压明显高于正常WR,差异有统计学意义(P0.01)。(2)SHR脑微动脉段上平滑肌细胞的Cinput和Ginput高于WR,差异有统计学意义(P0.05)。(3)2-APB可以浓度依赖性的降低脑微动脉段上平滑肌细胞的Cinput和Ginput(或者增加Rinput)。(4)2-APB抑制WR和SHR脑微动脉段上平滑肌细胞Ginput的IC50分别为0.21μmol/L和0.83μmol/L,差异有统计学意义(P0.05)。(5)2-APB浓度≥100μmol/L时,WR和SHR脑微动脉段上平滑肌细胞的Cinput、Ginput或Rinput与单个平滑肌细胞十分接近。由此可知,SHR较WR脑微动脉平滑肌细胞间缝隙连接耦联力增强,2-APB可以浓度依赖地抑制WR和SHR脑微动脉平滑肌细胞间缝隙连接,且对SHR的抑制效力较强。

The Effect of 2-APB on Gap Junction among Cerebral Arteriolar Smooth Muscle Cells in Wistar Rat and Spontaneously Hypertensive Rat

Objective to study the differences of electrophysiology and coupling force of the smooth muscle cells in the cerebral arteriolar segments between Wistar rat（WR） and Spontaneously Hypertensive rat（SHR）;to observe the effects of 2-Aminoethoxydiphenyl borate（2-APB） on the gap junction among the arterial smooth muscle cells.Methods Whole-cell patch clamp recordings were used to observe the 2-APB impaction on the arteriolar segment membrane′ s input capacitance（C（input））,input conductance（G（input）） and input resistance（R（input）） of the smooth muscle cells. Results（1） SBP of SHR was higher than that of WR,differences were statistically significant（P〈0.01）.（2） The Cinput and Ginput of the SHR arteriolar segment smooth muscle cells was much higher than that of the WR,differences were statistically significant（P〈0.05）.（3） 2-APB concentration-dependently reduced Cinputand Ginput（or increased Rinput） on smooth muscle cells.（4） IC50 of 2-APB Ginputsuppression of the WR and SHR were 0.21 and 0.83μmol/L respectively, differences were statistically significant（P〈0.05）.（5） After application of 2-APB concentration（≥100 μmol/L）,Cinput,Ginput and Rinput of the single smooth muscle cell was very close.Conclusion Gap junctional coupling is enhanced in smooth muscle cells of SHR cerebral artery.2-APB concentration-dependently inhibits gap junction among smooth muscle cells in WR and SHR cerebral arteriolar.The inhibitory potency is similar between two groups.When 2-APB concentration is ≥100 μmol/L,it can completely block gap junction among arteriolar smooth muscle cells.