Enteric plexus and interstitial cells of Cajal: Interrelationship in the stomach of Podarcis hispanica (Reptilia). An ultrastructural study

The ultrastructure organization of the stomach enteric plexus was examined in the lizard Podarcis hispanica. The ganglions of the myenteric plexus pre sent a low number of nerve cell bodies with a peculiar nucleus, which occas ionally establish direct contacts with cells of the circular muscle layer. Glial cells are smaller than the neurones, and their nucleus is very electr on-dense. They surround the axons that constitute the fibres of the myenter ic plexus. Four main types of axon profile are described in a morphological consideration of the vesicle population. In the interstice of the circular muscle layer we describe two types of interstitial cells that, due to thei r ultrastructural characteristics, may be equivalent to the interstitial ce lls of Cajal which have been described in mammalians. These cells shows par allel distribution to the stomach nerve plexuses, establishing close contac ts with them through their long cytoplasmic prolongations. By means of smal l gap-like unions, they contact both each other and the smooth muscle cells near them. We describe a submucous plexus, where neuronal bodies are scatt ered among bundles of nervous fibres, some of which are myelinated. A mucou s plexus with isolated neurones is located in the lamina propria. Axonal va ricosities containing vesicles contact with the cells of the mucous. Interc onnected interstitial cells may also be found in this plexus.