A model for the fast 4‐aminopyridine effects on amphibian myelinated nerve fibres. A study based on voltage‐clamp experiments
- 1 September 1989
- journal article
- research article
- Published by Wiley in Acta Physiologica Scandinavica
- Vol. 137 (1) , 53-61
- https://doi.org/10.1111/j.1748-1716.1989.tb08720.x
Abstract
The effect of 4-aminopyridine (4-AP) on the potassium currents in the node of Ranvier in myelinated nerve fibres was investigated with the voltage-clamp technique. The potential and time dependence of the currents in solutions with a high potassium concentration (114.5 mM) were studied. The block of the tail current was found to be less than that of the corresponding current during a potential step. Also, the time-course of the tail current was modified. In order to explain these findings, kinetic models of the 4-AP action were constructed and analysed numerically. A simple four-state model, in which 4-AP interacts only with open channels and where the binding is diphasically potential dependent, was found to account for the effects.Keywords
This publication has 23 references indexed in Scilit:
- Frequency dependent intermittency and ionic basis of impulse conduction in postganglionic sympathetic fibres of guinea-pig vas deferensNeuroscience, 1984
- Inactivation of the potassium transport system of myelinated nerve in the presence of a cyclic ionophoreActa Physiologica Scandinavica, 1982
- Evidence for the existence of three types of potassium channels in the frog Ranvier node membrane.The Journal of Physiology, 1981
- Microwave spectra and structure of the amine group in 3-aminopyridine and 4-aminopyridine. Ab initio molecular orbital calculations of the structure of the amine group in the aminopyridinesJournal of the Chemical Society, Faraday Transactions 2: Molecular and Chemical Physics, 1975
- Ionic pores, gates, and gating currentsQuarterly Reviews of Biophysics, 1974
- Ionic Currents at Resting Potential in Nerve Fibres from Xenopus laevis. Potential Clamp ExperimentsActa Physiologica Scandinavica, 1973
- Interaction of Tetraethylammonium Ion Derivatives with the Potassium Channels of Giant AxonsThe Journal of general physiology, 1971
- Inactivation of the Potassium Conductance and Related Phenomena Caused by Quaternary Ammonium Ion Injection in Squid AxonsThe Journal of general physiology, 1969
- Sodium currents in the myelinated nerve fibre of Xenopus laevis investigated with the voltage clamp techniqueThe Journal of Physiology, 1959
- Membrane currents in isolated frog nerve fibre under voltage clamp conditionsThe Journal of Physiology, 1958