Pacemaker shift in the gastric antrum of guinea-pigs produced by excitatory vagal stimulation involves intramuscular interstitial cells
Pacemaker shift in the gastric antrum of guinea-pigs produced by excitatory vagal stimulation involves intramuscular interstitial cells
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DOI：
10.1113/jphysiol.2002.018614
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发表时间：
2002-06-15
影响因子：
5.5
通讯作者：
Edwards, FR
中科院分区：
文献类型：
--
作者：
Hirst, GDS;Dickens, EJ;Edwards, FR
用离体豚鼠胃窦环行肌层肌束进行细胞内记录，并观察刺激内源性神经纤维所产生的反应。在消除了用apamin和L-硝基精氨酸（NOLA）刺激抑制性神经末梢的作用后，透壁神经刺激常常诱发小幅度兴奋性接头电位（EJP），并且总是诱发再生电位。神经元诱发的再生电位与直接刺激同一束神经元诱发的再生电位具有相似的特性。EJPs和神经诱发的再生电位被东莨菪碱消除，这表明两者都是由于乙酰胆碱的释放和毒蕈碱受体的激活。神经元诱发的再生电位，但不是EJPs，被废除的膜超极化，咖啡因和氯离子通道阻滞剂。在完整的胃窦，兴奋性迷走神经刺激增加慢波的频率。同时从肌间质细胞（ICCMY）和慢波的起搏电位的细胞内记录表明，每个起搏电位的发作通常先于每个慢波的发作，但迷走神经刺激引起每个慢波的发作先于每个起搏电位。总之，观察结果表明，在迷走神经刺激过程中，起搏器活动的起源发生了变化，慢波由肌内间质细胞（ICCMY）而不是ICCMY发起。
Intracellular recordings were made from isolated bundles of the circular muscle layer of guinea-pig gastric antrum and the responses produced by stimulating intrinsic nerve fibres were examined. After abolishing the effects of stimulating inhibitory nerve terminals with apamin and L-nitroarginine (NOLA), transmural nerve stimulation often evoked a small amplitude excitatory junction potential (EJP) and invariably evoked a regenerative potential. Neurally evoked regenerative potentials had similar properties to those evoked in the same bundle by direct stimulation. EJPs and neurally evoked regenerative potentials were abolished by hyoscine suggesting that both resulted from the release of acetylcholine and activation of muscarinic receptors. Neurally evoked regenerative potentials, but not EJPs, were abolished by membrane hyperpolarization, caffeine and chloride channel blockers. In the intact antrum, excitatory vagal nerve stimulation increased the frequency of slow waves. Simultaneous intracellular recordings of pacemaker potentials from myenteric interstitial cells (ICCMY) and slow waves showed that the onset of each pacemaker potential normally preceded the onset of each slow wave but vagal stimulation caused the onset of each slow wave to precede each pacemaker potential. Together the observations suggest that during vagal stimulation there is a change in the origin of pacemaker activity with slow waves being initiated by intramuscular interstitial cells (ICCMY) rather than by ICCMY.