Vagal mechanoreceptors of the inferior thoracic oesophagus, the lower oesophageal sphincter and the stomach in the sheep

Abstract

1. The unitary activity of 60 sensory vagal neurons was recorded from the nodose ganglion of anaesthetized young sheeps. They originated from the inferior thoracic oesophagus (14 receptors), from the lower oesophageal sphincter (16 receptors) and from the stomach (30 receptors). 2. The mechanoreceptors located in the inferior thoracic oesophagus were activated both by distension and contraction of the viscera. They belonged to slowly adapting type, except one receptor which gave an “on-off” effect during strong distensions. 3. The mechanoreceptors of the L.O.S. region were quite similar to oesophageal slowly adapting endings. However they often presented a tonic spontaneous activity which was sometimes modulated by the respiratory rhythm. 4. The gastric receptors were found in the different parts of the stomach: reticulum, rumen, oesophageal groove, but they were concentrated in the region including the oesophageal groove, the posterior part of the reticulum and the anterior part of the rumen. They adapted slowly to moderate mechanical stimulations (distension and contraction) and they presented in some cases spontaneous activity due to extrinsic or intrinsic contractions of the stomach or to the distension of the viscera. 5. The conduction velocity of the corresponding fibres was measured. The values obtained were respectively of 2.7–12.8m/s (mean: 5.7) for the oesophageal fibres, 1.0–1.3 m/s (mean: 1.1) for the L.O.S. fibres and 1.0–1.7m/s (mean: 1.3) for the gastric ones. Therefore the oesophageal ones were small sized myelinated fibres, whereas the others were non-medullated. The unitary activity of 60 sensory vagal neurons was recorded from the nodose ganglion of anaesthetized young sheeps. They originated from the inferior thoracic oesophagus (14 receptors), from the lower oesophageal sphincter (16 receptors) and from the stomach (30 receptors). The mechanoreceptors located in the inferior thoracic oesophagus were activated both by distension and contraction of the viscera. They belonged to slowly adapting type, except one receptor which gave an “on-off” effect during strong distensions. The mechanoreceptors of the L.O.S. region were quite similar to oesophageal slowly adapting endings. However they often presented a tonic spontaneous activity which was sometimes modulated by the respiratory rhythm. The gastric receptors were found in the different parts of the stomach: reticulum, rumen, oesophageal groove, but they were concentrated in the region including the oesophageal groove, the posterior part of the reticulum and the anterior part of the rumen. They adapted slowly to moderate mechanical stimulations (distension and contraction) and they presented in some cases spontaneous activity due to extrinsic or intrinsic contractions of the stomach or to the distension of the viscera. The conduction velocity of the corresponding fibres was measured. The values obtained were respectively of 2.7–12.8m/s (mean: 5.7) for the oesophageal fibres, 1.0–1.3 m/s (mean: 1.1) for the L.O.S. fibres and 1.0–1.7m/s (mean: 1.3) for the gastric ones. Therefore the oesophageal ones were small sized myelinated fibres, whereas the others were non-medullated.

DOI: 10.1007/BF00581145

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@article{Falempin1978VagalMO, title={Vagal mechanoreceptors of the inferior thoracic oesophagus, the lower oesophageal sphincter and the stomach in the sheep}, author={Maurice Falempin and No{\"{e}l Mei and J. P. Rousseau}, journal={Pfl{\"{u}gers Archiv}, year={1978}, volume={373}, pages={25-30} }