The role of muscarinic receptors in contractions of adult male Rat's isolated ileum

Background: The effects of cholinergic system are applied through both nicotine and muscarinic receptors. Considering to muscarinic receptorsexistence in therat ileum, in this researchthe effectof carbachol (muscarinic receptor agonist) and scopolamine (muscarinic receptor antagonists) on the ileum contraction induced by KCl in adult male rats were studied.\nMaterials and Methods: The distal part of Wistar rat’s ileum was separated and its contractions were recorded under one gr stretching and 37 degree temperature in the bathroom containing the solution of Tyrode by Isotonic method. The ileum tissue separately affected by KCl then carbachol in the first group, KCl then scopolamine in the second group, scopolamine for 30 minutes then KCl in the third group and 10-3 M concentration of scopolamine for 30 minutesthen 10-2 M concentration carbachol in the fourth group.\nResults: There was a significant difference between zero concentration and (10-2,10-3,10-4mg/ml) concentrations of carbachol (P<0.001). There was a significant difference between zero concentration and 10-3 M concentration of scopolamine (P<0.01) and also the values of 10-4, 10-6M (P<0.001). There was a significant difference between zero concentration and 10-3 M concentration of scopolamine (P<0.01) and also the values of 10-4M (P<0.001) and 10-6M (P<0.05) when scopolamine was exposed tissue for 30 minutes.\nConclusion: This study showed that different concentrations of carbachol enhance induced contraction by potassium chloride in a concentration-dependent manner and has a synergistic effect with potassium chloride. Also, different concentrations of scopolamine decrease induced contraction by potassium chloride in a concentration-dependent manner.