Effects of stretch on transient outward potassium and inward rectifier potassium current in cultured neonatal rat atrial myocytes |
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Authors: | XU Ya-nan YANG Long YANG Tian-he DENG Chun-yu LUO Lin QIN Zhi-fang TANG Qian YANG Jun |
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Affiliation: | 1.Department of Cardiology, Guizhou Provincial People’s Hospital Affiliated to Guiyang Medical College, Guiyang 550002, China;2.Department of Cardiology, The Third Affiliated Hospital of Zunyi Medical College, Zunyi 563003, China;3.Research Center of Medical Sciences, Guangdong Provincial People’s Hospital, Guangzhou 510080, China. |
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Abstract: | AIM:To investigate the effects of mechanical stretch on transient outward potassium current (Ito), inward rectifier potassium current (IK1) and action potential duration(APD) of cultured neonatal rat atrial myocytes. METHODS:Neonatal rat atrial myocytes were isolated and cultured on silicone sheeting with or without stretch for 24 h. The silicone membrane area was increased by 12% in stretched group. The cells without stretch served as control. Ito, IK1 and APD were recorded by the technique of whole-cell patch clamp. RESULTS:Compared with control group, Ito density in stretched myocytes was significantly reduced [(16±04) pA/pF vs (121±29) pA/pF, P<001], whereas IK1 density was increased [(-108±08) pA/pF vs (-88±09) pA/pF, P<001]. The APDs at 50% and 90% levels of repolarization (APD50 and APD90) in the stretched cells were obviously decreased than those in non-stretched cells [(105±14) ms vs (155±24) ms, (300±28) ms vs (563±36) ms, P<001]. CONCLUSION:Stretch stimulation leads to the reduction of Ito density, the increase in IK1 density and the shortness of APD in cultured rat atrial neonatal myocytes, which may contribute to atrial electrical remodeling induced by pressure overload. |
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Keywords: | Stretch Atrial myocytes Patch-clamp techniques Potassium current Action potential |
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