Nurgali, Kulmira, Nguyen, Trung V, Matsuyama, Hayato, Thacker, Michelle, Robbins, Heather L and Furness, John B (2007) Phenotypic changes of morphologically identified myenteric neurons following intestinal inflammation. Journal of Physiology (London), 583 (2). pp. 593-609. ISSN 0022-3751

Abstract

We investigated the responses of morphologically identifiedmyenteric neurons of the guinea-pig ileum to inflammation that was induced by the intraluminal injection of trinitrobenzene sulphonate, 6 or 7 days previously. Electrophysiological properties were examined with intracellular microelectrodes using in vitro preparations from the inflamed or control ileum. The neurons were injected with marker dyes during recording and later they were recovered for morphological examination. A proportion of neurons with Dogiel type I morphology, 45% (32/71), from the inflamed ileum had a changed phenotype. These neurons exhibited an actionpotential with a tetrodotoxin-resistant component, and aprolonged after-hyperpolarizing potential followed the action potential. Of the other 39 Dogiel type I neurons, no changes were observed in 36 and 3 had increased excitability. The afterhyperpolarizing potential (AHP) in Dogiel typeIneuronswasblockedby the intermediate conductance,Ca2+-dependentK+ channel blocker TRAM-34. Neurons which showed these phenotypic changes had anally directed axonal projections. Neither a tetrodotoxin-resistant action potential nor an AHP was seen in Dogiel type I neurons from control preparations. Dogiel type II neurons retained their distinguishing AH phenotype, including an inflection on the falling phase of the action potential, an AHP and, in over 90% of neurons, an absence of fast excitatory transmission. However, they became hyperexcitable and exhibited anodal break action potentials, which, unlike control Dogiel type II neurons, were not all blocked by the h current (Ih) antagonist Cs+. It is concluded that inflammation selectively affects different classes ofmyenteric neuronsandcauses specific changes in their electrophysiological properties.

Search Google Scholar

Repository staff login