Gastric Emptying and Ca2+ and K+ Channels of Circular Smooth Muscle Cells in Diet-Induced Obese Prone and Resistant Rats
Gastric Emptying and Ca2+ and K+ Channels of Circular Smooth Muscle Cells in Diet-Induced Obese Prone and Resistant Rats
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DOI：
10.1002/oby.20021
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发表时间：
2013-02-01
期刊：
影响因子：
6.9
通讯作者：
Chen, Jiande D. Z.
中科院分区：
文献类型：
--
作者：
Li, Shiying;Maude-Griffin, Roland;Chen, Jiande D. Z.
目的：胃排空加速导致饥饿和频繁进食可能是肥胖发生的一个潜在因素。本研究的目的是研究饮食诱导肥胖倾向(DIO-P)和DIO抵抗(DIO-R)大鼠的胃排空，并探讨胃窦环状平滑肌细胞(SMC)钙(Ca~(2+))和钾(K~+)通道电特性的可能差异。设计和方法：采用全细胞膜片钳技术测定单个SMC的钙、钾电流。在摄入固体食物90分钟后评估胃排空功能。结果：DIO-P大鼠固体胃排空速度明显快于DIO-R大鼠。DIO-P大鼠的L钙电流(I-BA、I-L)的峰值在10 mV时明显大于DIO-R大鼠，但不改变电流-电压曲线和电压依赖性的激活和失活。与DIO-R大鼠相比，DIO-P大鼠瞬时外向钾电流的半最大失活电压(I-Kto)去极化程度更高(接近4 mV)。两组间I-Kto的电流密度和恢复动力学无明显差异。DIO-P大鼠延迟整流钾电流(I-KDR)对四乙基氯化铵敏感，4-氨基吡啶不敏感，其电流密度低于DIO-R。结论：DIO-P大鼠胃排空加快可能与胃窦SMC内I-BA、I-L浓度升高、I-Kto失活曲线去极化、I-KdR密度降低有关。
Objective: Accelerated gastric emptying that precipitates hunger and frequent eating could be a potential factor in the development of obesity. The aim of this study was to study gastric emptying in diet-induced obese-prone (DIO-P) and DIO-resistant (DIO-R) rats and explore possible differences in electrical properties of calcium (Ca2+) and potassium (K+) channels of antral circular smooth muscle cells (SMCs). Design and Methods: Whole-cell patch-clamp technique was used to measure Ca2+ and K+ currents in single SMCs. Gastric emptying was evaluated 90 min after the ingestion of a solid meal. Results: Solid gastric emptying in the DIO-P rats was significantly faster compared with that in the DIO-R rats. The peak amplitude of L-type Ca2+ current (I-Ba,I-L) at 10 mV in DIO-P rats was greater than that in DIO-R rats without alternation of the current-voltage curve and voltage-dependent activation and inactivation. The half-maximal inactivation voltage of transient outward K+ current (I-Kto) was more depolarized (similar to 4 mV) in DIO-P rats compared with that in DIO-R rats. No difference was found in the current density or recovery kinetics of I-Kto between two groups. The current density of delayed rectifier K+ current (I-Kdr), which was sensitive to tetraethylammonium chloride but not 4-aminopyridine, was lower in DIO-P rats than that in DIO-R rats. Conclusion: The accelerated gastric emptying in DIO-P rats might be attributed to a higher density of I-Ba,I-L, depolarizing shift of inactivation curve of I-Kto and lower density of I-Kdr observed in the antral SMCs of DIO-P rats.