AIM: To investigate the relationship between M3-R/IK(M3) and arrhythmia in order to find a new target for antiarrhythmic agents. METHODS: Using the acute ischemic model of rats and patch-clamp techniques, the effects of the M3 receptor on the occurrence of arrhythmias and its possible mechanisms were studied. RESULTS: In acute ischemic model of rats, the M3 receptor antagonist 4-diphenylacetoxy-N-methylpiperidine-methiodide (4DAMP) increased the occurrence of arrhythmias, and the M3 receptor agonist choline suppressed the onset and the development of arrhythmias (P < 0. 01). No change was observed after treatment with other receptor antagonists (M1, M2, and M4). With patch-clamp techniques, it was found that choline induced K+ current could be inhibited by 4DAMP. Antagonists toward M1, M2, and M4 receptors all failed to alter the current. CONCLUSION: Choline modulates the cellular electrical properties of the heart, probably by activating a K+ current via stimulation of the M3 receptor. M3-R/IK(M3) may act as a new target for antiarrhythmic agents.
AIM: To investigate the relationship between M3-R/IK(M3) and arrhythmia in order to find a new target for antiarrhythmic agents. METHODS: Using the acute ischemic model of rats and patch-clamp techniques, the effects of the M3 receptor on the occurrence of arrhythmias and its possible mechanisms were studied. RESULTS: In acute ischemic model of rats, the M3 receptor antagonist 4-diphenylacetoxy-N-methylpiperidine-methiodide (4DAMP) increased the occurrence of arrhythmias, and the M3 receptor agonist choline suppressed the onset and the development of arrhythmias (P < 0. 01). No change was observed after treatment with other receptor antagonists (M1, M2, and M4). With patch-clamp techniques, it was found that choline induced K+ current could be inhibited by 4DAMP. Antagonists toward M1, M2, and M4 receptors all failed to alter the current. CONCLUSION:Choline modulates the cellular electrical properties of the heart, probably by activating a K+ current via stimulation of the M3 receptor. M3-R/IK(M3) may act as a new target for antiarrhythmic agents.