The enteric nervous system in the ruminant stomach of the sheep (Ovis aries).

textabstractNotwithstanding the enormous importance of the pathology of the ruminant stomach in veterinary medicine (and hence in economy) and the fact that adequate functioning of this gastrointestinal segment largely depends upon the integrity of the enteric nervous system, it is rather surprising to ascertain that little or no basic information concerning the intramural innervation of the ruminant stomach is available in the literature. Nevertheless, if we are to have any chance of understanding and treating the abnormalities in the mechanisms underlying the various diseases of the stomach (chronic ruminal tympany, displacement of the abomasum etc.), it is imperative to have detailed information on its innervation. In an attempt to fill this lacuna in our knowledge a morphological study of the intramural nervous system of the stomach of sheep was undertaken. This study had the following aims: to demonstrate the intramural neuro-endocrine complex (Part II); to obtain an overall picture of the intramural innervation of the different compartments of the stomach (Part II); to study some substances which are known to be actively present in the ENS of other mammalian species; and to study the effect of these substances on the smooth muscle tone of the different segments of the stomach. To attain the above-mentioned objectives this study has been planned in three phases. In the first phase (Part I) some introductory remarks concerning the morphology and functions of the ruminant stomach and the autonomic nervous system will be given. Thereafter, much attention will be paid to the morphology, the neurochemistry, the functional significance and to some clinical aspects of the ENS. The principal data arising from this review will function as the key-stones for the original part i.e. Part II and III of this study. The aim of the second phase (Part II) is to gain an overall picture of the architecture of the intramural innervation of the ruminant stomach, using an antiserum for neuron specific enolase. In the third and last phase of this study the results emerging from Part II will be further neurochemically differentiated. Finally, the effect of the immunohistochemically established neurotransmitters/modulators on the muscle tone of the ruminant stomach will be studied