Volume-sensitive synaptic input to neurons in guinea pig inferior mesenteric ganglion.
Volume-sensitive synaptic input to neurons in guinea pig inferior mesenteric ganglion.
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豚鼠肠系膜下神经节神经元的体积敏感突触输入。
DOI：
10.1152/ajpgi.1990.259.3.g490
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发表时间：
1990
期刊：
影响因子：
--
通讯作者：
Kreulen,DL
中科院分区：
文献类型：
--
作者：
Anthony,TL;Kreulen,DL
在体外研究肠系膜下神经节(IMG)神经元细胞内记录的突触电位与与推进性收缩相关的结肠体积变化之间的关系。结肠扩张引起推进性收缩(频率为2-5次/分钟)，使结肠内容量减少88%。S每次推进收缩持续10-12次，之后结肠重新充盈。持续的推进性收缩与快速胆碱能兴奋性突触后电位(EPSP)的幅度和频率降低以及慢EPSP的部分复极有关。结肠段的压力-容量关系有两条肢体：当扩张压力小于15cmH2O时，结肠内体积与扩张压力成正比，大于15cmH2O(压力肢)时，结肠内体积不再增加。突触输入的变化与这些压力-体积关系有关。在体积肢，快电位的频率和波幅与结肠内体积成正比，并随体积增大而增大。在受压肢体，膜有缓慢的去极化，并随着扩张压力的增加而增加。在等容量条件下，与结肠收缩相关的腔内压力的变化与IMG神经元兴奋性突触输入的变化无关。这些实验表明，结肠IMG神经元的机械感受器对结肠内容量和压力都很敏感。
The relationship between changes in intracolonic volume related to propulsive contractions and synaptic potentials recorded intracellularly in neurons in the inferior mesenteric ganglion (IMG) was investigated in vitro. Distension of the colon induced propulsive contractions (frequency, 2-5/min), which reduced intracolonic volume by 88%. Each propulsive contraction was sustained for 10-12 s, after which time the colon refilled. The sustained propulsive contractions were associated with a decrease in the amplitude and frequency of fast cholinergic excitatory postsynaptic potentials (EPSPs) and partial repolarization of the slow EPSP. The pressure-volume relationships of the colonic segments had two limbs: at distension pressures less than 15 cmH2O ("volume limb") the intracolonic volume was proportional to the distension pressure; greater than 15 cmH2O ("pressure limb") the intracolonic volume did not increase further. The changes in synaptic input were related to these pressure-volume relationships. In the volume limb, the frequency and amplitude of fast EPSPs were proportional to intracolonic volume and maximized with volume. In the pressure limb, there was a slow depolarization of the membrane that increased with greater distension pressures. Under isovolumic conditions, the changes in intraluminal pressure associated with colonic contractions were not associated with changes in excitatory synaptic input to IMG neurons. These experiments demonstrate that colonic mechanoreceptors to IMG neurons are sensitive to both intracolonic volume and pressure.