Effects of chronic prednisolone treatment on postjunctional membrane responses to agonist.
Using frogs treated 1 month with prednisolone, we studied responses of the muscle postjunctional membrane to acetylcholine and carbamylcholine. In control muscles following a bath application of 3 microM neostigmine or 30 microM pyridostigmine, there was an increased depolarization response to iontophoretically applied acetylcholine or carbamylcholine. Results with prednisolone-treated frog muscle were essentially identical. In some fibers of prednisolone-treated muscle there was a decrementing response to repetitive iontophoretic application of carbamylcholine. Prolonged administration of prednisolone may accelerate desensitization of acetylcholine receptors during repetitive application of agonist.
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Department of Physiology, Columbia University, New York, NY.
Nastuk
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D000109:Acetylcholine / Q000494:pharmacology; D000818:Animals; D002217:Carbachol / Q000494:pharmacology; D009388:Neostigmine / Q000494:pharmacology; D009469:Neuromuscular Junction / Q000187:drug effects* / Q000502:physiology; D011239:Prednisolone / Q000494:pharmacology*; D011729:Pyridostigmine Bromide / Q000494:pharmacology; D011894:Rana pipiens; D011950:Receptors, Cholinergic / Q000187:drug effects*; D009435:Synaptic Transmission / Q000187:drug effects; D013997:Time Factors
D011950:Receptors, Cholinergic; D009388:Neostigmine; D002217:Carbachol; D011239:Prednisolone; D011729:Pyridostigmine Bromide; D000109:Acetylcholine