Two‐component desensitization at the neuromuscular junction of the frog.
- 1 March 1983
- journal article
- research article
- Published by Wiley in The Journal of Physiology
- Vol. 336 (1), 229-241
- https://doi.org/10.1113/jphysiol.1983.sp014578
Abstract
Desensitization to ionophoretically applied ACh has been studied at voltage‐clamped neuromuscular junctions of Rana pipiens. The time courses of both the onset of and recovery from desensitization displayed two components. The application of metabolic inhibitors to the preparation decreased the degree of recovery and also decreased both time constants of onset. The effect on onset was more pronounced on the slow component while no effect selective for either of the two components of recovery was seen. Intracellular injection of EGTA into the muscle cell increased both time constants of desensitization onset. The effect was much more pronounced on the slow component. Increasing the dose of ACh selectively decreased the fast time constant of desensitization onset. The effect was more selective in low‐calcium than normal Ringer solution. These observations suggest that there are at least two independent mechanisms in the process of desensitization at the neuromuscular junction. These mechanisms differ in time course, degree of dependency on [Ca]i, and sensitivity to acetylcholine dose.This publication has 22 references indexed in Scilit:
- A CRITIQUE OF COMPARTMENTAL ANALYSISAnnual Review of Biophysics and Bioengineering, 1981
- Mechanisms of Synaptic ModulationInternational Review of Neurobiology, 1981
- DESENSITIZATION OF THE ACETYLCHOLINE RECEPTOR OF DENERVATED RAT SOLEUS MUSCLE AND THE EFFECT OF CALCIUMBritish Journal of Pharmacology, 1980
- THE REGULATION OF INTRACELLULAR CALCIUM BY MITOCHONDRIA*Annals of the New York Academy of Sciences, 1978
- EFFECT OF IONOPHORE X‐537A ON DESENSITIZATION RATE AND TENSION DEVELOPMENT IN POTASSIUM‐DEPOLARIZED MUSCLE FIBRESBritish Journal of Pharmacology, 1976
- Acetylcholine Receptors in Muscle FibresNature, 1971
- The Effect of Calcium on the Desensitization of Membrane Receptors at the Neuromuscular JunctionThe Journal of general physiology, 1966
- Effects of the Intracellular Ca Ion Concentration upon the Excitability of the Muscle Fiber Membrane of a BarnacleThe Journal of general physiology, 1966
- The dependence of contraction and relaxation of muscle fibres from the crab Maia squinado on the internal concentration of free calcium ionsBiochimica et Biophysica Acta (BBA) - Specialized Section on Biophysical Subjects, 1964
- A study of the ‘desensitization’ produced by acetylcholine at the motor end‐plateThe Journal of Physiology, 1957