Effects Of M ₂ And M Cholinergic Receptors On Small Intestine Movement In Rats With Spleen Qi Deficiency

Purpose:In the basic theory of traditional Chinese Medicine, spleen governs the transportation and transformation, which including the action of the small intestine(SI) movement. When spleen qi deficiency occurs the reduced SI movement can be observed, however, its mechanism is unclear. It is known that the SI movement is enhanced when the vagi are excited via the release of acetylcholine(ACh) which activates cholinergic receptors. In the SI smooth muscle, M2 receptor(M2R) and M3 receptor(M3R) are major receptors, and their actions in spleen qi deficiency are not known. In the present study, the roles of M2 R and M3 R in the small intestine(SI) movement of spleen Qi deficiency rats were detected.Material and method:16 male SD rats were randomly divided in the control and spleen qi deficiency(model group) groups, 8 rats in each group; Spleen qi deficiency model of improper diet and overfatigue type was established; The SI propelling rate was used to valuate the SI motion; the ultrastructure of the SI was observed by the light and electron microscope; ELISA was used to measure the ACh, c AMPand PKA concentrations in SI tissue; Immohistochemistry was employed to test expressions of M2 R and M3 R.Results:1. Comapraed with those in the control, the body mass, food and water intakes were all decreased, both the motion distance and vertical times in the open field were reduced, and the forelimb strength was decreased, significantly, in the model group. 2.The SI propelling rate in the model group was significantly less than that in the control. 3.The SI structures in the control were normal, for example, villi were abundant and well ranged, cell organs showed the normal morphology, however, some villi were deleted, local membranes were separated, and mitochondria showed distended. 4.Compared with those in the control, the SI tissue ACh level was not changed, M2 R expression was markedly increased, while M3 R expression and c AMP, PKA concentration were significantly decreased, in the model group.Conclusion:1. The reduction of the SI motion in spleen qi deficiency is related to the upregulation of M2 R and downregulation of M3 R.