Spatial organization and coordination of slow waves in the mouse anorectum
Spatial organization and coordination of slow waves in the mouse anorectum
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DOI：
10.1113/jphysiol.2014.272542
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发表时间：
2014-09-01
影响因子：
5.5
通讯作者：
Keef, K. D.
中科院分区：
文献类型：
--
作者：
Hall, K. A.;Ward, S. M.;Keef, K. D.
内肛门括约肌（IAS）发展张力，对维持高肛门压力很重要，而直肠张力较低。在IAS中负责音调产生的机制仍然不确定。本研究通过比较小鼠IAS和远端直肠的电特性和形态来解决这个问题。IAS的张力幅值和相位收缩频率大于直肠，而IAS的膜电位（E-m）负电位小于直肠。慢波（SWs）在IAS远端振幅和频率最大，在口腔方向下降。双微电极记录显示，SWs在圆周方向上的协调距离比在口腔方向上的协调距离大得多。IAS的圆形肌层被结缔组织分隔成5 - 8个小束，而直肠中很少有小束存在。SWs在口腔方向的有限协调表明邻近小束的活动不协调。肌内间质细胞Cajal和血小板衍生的生长因子受体α阳性细胞存在于每个小束中，表明这两种细胞中的一种或两种在SW的产生中起作用。综上所述，将IAS与远端直肠区分开来的三个重要特征：(1)更去极化的E-m；(2)波形更大、频率更高；(3)肌肉的多单元结构。所有这些特征都可能导致IAS比远端直肠产生更大的张力。
The internal anal sphincter (IAS) develops tone and is important for maintaining a high anal pressure while tone in the rectum is less. The mechanisms responsible for tone generation in the IAS are still uncertain. The present study addressed this question by comparing the electrical properties and morphology of the mouse IAS and distal rectum. The amplitude of tone and the frequency of phasic contractions was greater in the IAS than in rectum while membrane potential (E-m) was less negative in the IAS than in rectum. Slow waves (SWs) were of greatest amplitude and frequency at the distal end of the IAS, declining in the oral direction. Dual microelectrode recordings revealed that SWs were coordinated over a much greater distance in the circumferential direction than in the oral direction. The circular muscle layer of the IAS was divided into five to eight minibundles' separated by connective tissue septa whereas few septa were present in the rectum. The limited coordination of SWs in the oral direction suggests that the activity in adjacent minibundles is not coordinated. Intramuscular interstitial cells of Cajal and platelet-derived growth factor receptor alpha-positive cells were present in each minibundle suggesting a role for one or both of these cells in SW generation. In summary, three important properties distinguish the IAS from the distal rectum: (1) a more depolarized E-m; (2) larger and higher frequency SWs; and (3) the multiunit configuration of the muscle. All of these characteristics may contribute to greater tone generation in the IAS than in the distal rectum.