| Popis: |
From the oesophagus to the rectum, the muscularis mucosae comprises a thin layer of smooth muscle at the base of the digestive tract mucosa. Although the anatomic relations of the muscularis mucosae are well described, its physiological role is still only hypothesized. The muscularis mucosae could be implicated in the different functions of the digestive tract wall including absorption, secretion and protection. Modified function could be an early sign of certain pathological situations. The aim of this work was to investigate, in a dog model, the motor function of the muscularis mucosae by using an original technique for recording electromyograms and by comparing the electrical activity generated by the muscularis mucosae with the activity of the external muscle layers of the colon. We were able to demonstrate that in situ, the muscularis mucosae generates regular rhythmic electrical signals: slow wave patterns with rare episodes of rapid activity and sporadic action potentials. This rapid myoelectrical activity was not correlated with the much more intense activity of the external muscle layer responsible for the mechanical motor function of the colic wall. Finally, the motor activity of the muscularis mucosae appeared to be regulated and modulated by certain neurohormonal factors such as substance P. |
