Desensitization of the muscarinic receptor of bullfrog atrial muscle

Summary The muscarinic ACh receptors, which hyperpolarize the resting membrane and also depress the action potential of bullfrog atrial muscle, show desensitization to the action of ACh. This suggests that the molecular mechanism of these muscarinic ACh receptor-ionic channel (voltage-dependent) complexes is comparable to that of the nicotinic ACh receptor-ionic channel (voltage-independent) complex of the end-plate.Acknowledgment. This work was supported by a grant-in-aid for Scientific Research from the Ministry of Education, Science and Culture of Japan.