Autonomous Distributed Control Systems in the Enteric Nervous System

所有研究人员的报告总结如下：研究表明，虽然引起蠕动的能力受损，但在机械切除粘膜和粘膜下层的豚鼠回肠中，仍能保留诱发蠕动的能力。三磷酸腺苷和L多巴可调节豚鼠回肠和盲肠肠道神经系统递质的释放。在豚鼠肠缺血的体外模型中，只有少数肌间神经元表现出典型的神经细胞膜反应，表明缺血损伤，而其他肌间和粘膜下神经元的电特性和突触传递没有改变。神经肽Y(NPY，1-100 nM)可抑制豚鼠盲肠黏膜下丛中的慢IPSP；NPY不影响细胞的电生理特性，也不影响慢IPSP的中介物去甲肾上腺素的反应。此外，在300 nm以下，NPY对快、慢诱发电位均无明显影响。因此，NPY可能只作用于突触前和选择性地抑制去甲肾上腺素的释放。与盲肠相比，在降结肠的神经元中出现慢的IPSP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。Broca斜角带的胆碱能神经元是从胎儿或新生大鼠中分离出来的，并进行了培养。对这些神经元的组织化学和免疫细胞化学研究表明，甚至在突触形成之前，生长锥体中就存在高水平的胆碱能代谢。观察到生长球果丝状突起对高钾刺激的快速伸长。可能附着在生长锥膜上的Con-A包覆金颗粒在一定的限制区域内以明显的布朗方式运动，并可通过激光镊子来控制其运动。

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.