The muscularis mucosae of the human stomach

Abstract

There exist only a few papers concerning the physiology of the muscularis mucosae only one which deals with the muscularis mucosae of the human stomach in any detail (Thorell, 1927). The purposes of this investigation were twofold: (1) to determine what difference, if any, existed between the responses to drugs of the muscularis mucosae taken from different regions of the human stomach, and (2) to see whether any information could be obtained about the role of the submucous plexus in controlling the activity of the muscularis mucosae. METHODS Preparations of gastric muscularis mucosne were made from fresh human material obtained from the operating theatre. The method of preparation closely resembled that of King et al. (1947). Longitudinal or transverse strips of stomach wall 6 cm long and 2 cm wide were cut out and the outer muscle coats dissected off by cutting along the plane of the loose submucous layer. In order to ensure that the muscularis mucosae was adequately exposed to the saline in the bath and the strip did not curl up with the mucous surface outermost as naturally happens, the strips were made up into cylinders (with the mucosal surface inside), by inserting a series of interrupted cotton stitches through the edges of the long sides of the strip and drawing them together. This also helped to ensure that any mucus secreted by the mucous membrane did not gain free access to the saline bath. The upper and lower ends of the strip were kept closed by the threads securing them to the writing lever and to the fixed hook at the bottom of the bath respectively. Excessive contamination of the bath by mucus always interferred with the sensitivity of the muscle to drugs. The cylinder of tissue thus prepared was mounted in a bath containing 60 ml. of magnesium-free Tyrode's solution, oxygen being continuously bubbled through the solution which was kept at 370 C. Strips prepared in this way remained active for many hours. A very light, carefully balanced, frontal writing point lever giving a magnification x 20 was attached to one end of the strip of tissue and made to record the contractions on a smoked drum. In all tracings contraction is indicated by upward excursion of the pointer. The drugs employed were acetylcholine chloride, L-adrenaline hydrochloride, DL-noradrenaline succinate, nicotine tartrate, histamine acid phosphate (the concentrations of histamine mentioned refer to the base), atropine sulphate, hexamethonium bromide, ergotoxine ethanesulphonate and vasopressin (Pitressin).

The muscularis mucosae of the oesophagus of the cat, rabbit and rat

“…The inhibitory response is more readily obtained as judged by the concentrations necessary to elicit both types of reaction. On the other hand, Walder (1953) found that human gastric muscularis mucosae from the greater curvature contracted to adrenaline, while that from the lesser curvature relaxed. Others (Gunn & Underhill, 1914;King & Church, 1923;King & Robinson, 1945) have reported contraction of intestinal muscularis mucosae in response to adrenaline, but not relaxation.…”

A pharmacological study of oesophageal muscularis mucosae from the cat, dog and American opossum (Didelphis virginiana)

“…The other peptides used were ineffective on tissues from all three species. In this lack of peptide sensitivity, the muscularis mucosae of the oesophagus contrasts with that of human stomach (Walder, 1953), dog stomach and colon (Angel et al, 1980;1983), which have been found to be sensitive to the actions of a variety of peptides. This implies that peptides have little place in regulation of the gross movements of the oesophageal muscularis mucosae, although they might be involved in interneuronal transmission or act as neuromodulators.…”

“…Although the muscularis mucosae of the stomach, 1923: King & Robinson, 1945: King et al, 1947: Walder, 1953: Onori et al, 1971: Gallacher et al, 1973: Angel et al, 1982 little is known of the pharmacology of oesophageal muscularis mucosae. Early studies by Hughes (1955;1957) showed that oesophageal muscularis mucosae from the cat, rabbit, rat and human foetus were contracted by acetylcholine and pilocarpine and, with the exception of human foetal tissue were, depending on resting tone, relaxed by adrenaline.…”

Muscularis mucosae - the forgotten sibling

“…Human gastric muscularis mucosae showed contraction to acetylcholine, but is insensitive to histamine (Walder, 1953). In contrast to human, dog gastric muscularis mucosae possessed both contractile H1 and relaxant H2 receptors (Muller et al, 1993).…”

“…(1) Human: The muscularis mucosae isolated from different directions of the human stomach spontaneously developed resting tone and motor activity whose were varied from preparation to preparation (Walder, 1953). Nicotine produced both contractile and relaxant responses of the muscularis mucosae which were also different from preparation to preparation.…”