Components of desensitization at the frog neuromuscular junction and the effect of metabolic inhibitors

Abstract

1. The physiological responses to many hormones and neurotransmitters decrement with time in the continued presence of the agonist. 2. This process, variously termed desensitization, tachyphylaxis and receptor inactivation, has been demonstrated to occur at many receptors but remains poorly understood. 3. The effect of the application of metabolic inhibitors on the rate of desensitization at the neuromuscular junction of the frog has been investigated to test the possible role of intracellular calcium (Ca i ) in the desensitization mechanism. 4. Desensitization curves recorded under voltage clamp in response to the cholinergic agonist carbachol have been found to display two time constants. 5. The application of metabolic inhibitors decreased the slow time constant but not the fast one. 6. Treatment of the muscles with metabolic inhibitors also decreased the degree of recovery from desensitization. 7. The data are consistent with a role of Ca i in the desensitization process. The physiological responses to many hormones and neurotransmitters decrement with time in the continued presence of the agonist. This process, variously termed desensitization, tachyphylaxis and receptor inactivation, has been demonstrated to occur at many receptors but remains poorly understood. The effect of the application of metabolic inhibitors on the rate of desensitization at the neuromuscular junction of the frog has been investigated to test the possible role of intracellular calcium (Ca i ) in the desensitization mechanism. Desensitization curves recorded under voltage clamp in response to the cholinergic agonist carbachol have been found to display two time constants. The application of metabolic inhibitors decreased the slow time constant but not the fast one. Treatment of the muscles with metabolic inhibitors also decreased the degree of recovery from desensitization. The data are consistent with a role of Ca i in the desensitization process.

DOI: 10.1007/BF00735068

2 Figures and Tables

Cite this paper

@article{Chesnut2004ComponentsOD, title={Components of desensitization at the frog neuromuscular junction and the effect of metabolic inhibitors}, author={Thomas J. Chesnut}, journal={Cellular and Molecular Neurobiology}, year={2004}, volume={2}, pages={59-63} }