Desensitization of the acetylcholine receptor of denervated rat soleus muscle and the effect of calcium.
1 Desensitization of the extrajunctional acetylcholine receptors of denervated rat soleus muscle has been studied by evoking iontophoretic acetylcholine potentials at a high frequency (10 Hz). 2 Desensitization occurred with a slow and at least one fast component. 3 Increasing the dose of acetylcholine decreased the half time of onset of desensitization, but did not alter recovery half time. 4 Alteration of external calcium between 0 and 50 mM, or perfusion with agents which increase intracellular calcium such as 2,4-dinitrophenol and the calcium ionophores, X537A and A23187, did not alter desensitization half time. 5 The cholinoceptor agonists acetylcholine, acetylthiocholine, tetramethylammonium and phenyltrimethylammonium all caused desensitization at the same rate.
D000109:Acetylcholine / Q000378:metabolism / Q000494:pharmacology; D000818:Animals; D000001:Calcimycin / Q000494:pharmacology; D002118:Calcium / Q000494:pharmacology*; D004140:Dinitrophenols / Q000494:pharmacology; D005260:Female; D066298:In Vitro Techniques; D007832:Lasalocid / Q000494:pharmacology; D009121:Muscle Denervation; D009132:Muscles / Q000187:drug effects* / Q000294:innervation; D051381:Rats; D011950:Receptors, Cholinergic / Q000187:drug effects*; D013997:Time Factors
D004140:Dinitrophenols; D011950:Receptors, Cholinergic; D000001:Calcimycin; D000109:Acetylcholine; D002118:Calcium; D007832:Lasalocid