Beckett E A H, Bayguinov Y R, Sanders K M, Ward S M, Hirst G D S
Department of Physiology and Cell Biology, University of Nevada School of Medicine, Reno, USA.
J Physiol. 2004 Aug 15;559(Pt 1):259-69. doi: 10.1113/jphysiol.2004.063016. Epub 2004 Jun 24.
Intracellular recordings were made from isolated bundles of the circular muscle layer of mouse and guinea-pig gastric fundus. These preparations displayed an ongoing discharge of membrane noise (unitary potentials), similar to that recorded from similar preparations made from the circular layer of the antrum. Bundles of muscle from the fundus of W/W(V) mice, which lack intramuscular interstitial cells of Cajal (ICC(IM)) lacked the discharge of membrane noise observed in wild-type tissues. When the membrane potential was changed by passing depolarizing or hyperpolarizing current pulses, the discharge of membrane noise was little changed. The membrane noise was unaffected by adding chloride channel blockers; however, agents which buffered the internal concentration of calcium ions reduced the discharge of membrane noise. Treatment of tissues with CCCP, which interferes with the uptake of calcium ions by mitochondria, also reduced the membrane noise and caused membrane hyperpolarization. Similar observations were made on bundles of tissue isolated from the circular layer of the guinea pig antrum. Together the observations indicate that membrane noise is generated by a pathway located in ICC(IM). The properties of this pathway appear to vary dramatically within a given organ. The lack of voltage sensitivity of the discharge of membrane noise in the fundus provides a possible explanation for the lack of rhythmic electrical activity in this region of the stomach.
从小鼠和豚鼠胃底环形肌层分离出的肌束进行细胞内记录。这些标本显示出持续的膜噪声放电（单位电位），类似于从胃窦环形层制备的类似标本所记录到的情况。来自W/W（V）小鼠胃底的肌束，缺乏肌内Cajal间质细胞（ICC（IM）），缺乏在野生型组织中观察到的膜噪声放电。当通过施加去极化或超极化电流脉冲改变膜电位时，膜噪声放电变化很小。膜噪声不受添加氯离子通道阻滞剂的影响；然而，缓冲细胞内钙离子浓度的试剂会减少膜噪声放电。用CCCP处理组织，CCCP会干扰线粒体对钙离子的摄取，也会减少膜噪声并导致膜超极化。对从豚鼠胃窦环形层分离出的组织束也进行了类似的观察。这些观察结果共同表明，膜噪声是由位于ICC（IM）中的一条途径产生的。在给定器官内，这条途径的特性似乎有很大差异。胃底膜噪声放电缺乏电压敏感性，这为胃的这个区域缺乏节律性电活动提供了一个可能的解释。
