Autonomous Distributed Control Systems in the Enteric Nervous System

所有调查人员的报告总结如下。结果表明，在机械去除粘膜和粘膜下层的离体豚鼠回肠中，刺激肠蠕动的能力虽然受损，但仍能保留。ATP和左旋多巴调节豚鼠回肠和盲肠肠神经系统的递质释放。在使用豚鼠的体外肠缺血模型中，只有少数肌肠神经元表现出表明缺血损伤的“经典”神经元膜反应，而其他肌肠和粘膜下神经元的电学性质或突触传递没有变化。发现神经肽Y （NPY, 1 ~ 100 nM）对豚鼠盲肠粘膜下神经丛的慢速ipsp有抑制作用；NPY不影响电生理特性，也不影响细胞对去甲肾上腺素的反应，去甲肾上腺素是缓慢ipsp的介质。在300 nM以内，NPY对快、慢速epsp均无明显影响。因此，NPY可能仅在突触前和选择性地抑制去甲肾上腺素的释放。与盲肠神经元相比，降结肠神经元中ipsp的缓慢发生是罕见的。这是肠神经元功能区域差异的另一个重要例子的初步证据。从胎儿或新生大鼠身上分离布洛卡斜带胆碱能神经元，并进行培养。对这些神经元的组织和免疫细胞化学研究表明，在突触形成之前，生长锥就存在高水平的胆碱能代谢。在高钾刺激下，生长球果的丝状伪体迅速伸长。可能附着在生长锥膜上的con - a涂层金颗粒在一定的限定区域内以布朗方式运动，其运动可以用激光镊子来控制。

Reports from all investigators are summarized as follows.It was demonstrated that the ability of provoking peristalsis, though impaired, could be preserved in the isolated guinea-pig ileum from which both mucosa and submucosa were mechanically removed. ATP and L-DOPA modulated transmitter release in the enteric nervous system of the guinea-pig ileum and caecum.In the in vitro models of intestinal ischaemia using guinea-pigs, only a few myenteric neurons showed the 'classical' neuronal membrane response indicative of ischaemic damage, whereas other myenteric and submucous neurons showed no change in their electrical properties or synaptic transmission.Neuropeptide Y (NPY, 1-100 nM) was found to inhibit the slow IPSPs in the caecum submucous plexus of guinea-pigs ; NPY did not affect the electrophysiological properties nor the response of the cells to noradrenaline, the mediator for the slow IPSPs. Moreover, up to 300 nM, NPY had no detectable effect on the fast and slow EPSPs. Thus, NPY might act only presynaptically and selectively to depress noradrenaline release. The slow IPSPs were rare events in neurons of the descending colon, compared with the caecum. This is preliminary evidence for another important example of regional differences in the function of the enteric neurons.Cholinergic neurons of the diagonal band of Broca were isolated from fetus or new-born rats and were kept in culture. Histo- and immunocytochemical invesstigations on these neurons disclosed the presence of cholinergic metabolism in growth cones at high level even before synapse-formation. Rapid elongation of filopoida from growth cones was observed in response to high potassium stimulation. Con-A-coated gold particles possibly attached to growth cone membrane moved apparently in a Brownian manner within some restricted area, and their movement could be controlled by means of laser tweezers.