Kinetics of the TEA and 4-AP sensitive K+ current in the slowly adapting lobster stretch receptor neurone
- 1 June 1983
- journal article
- research article
- Published by Wiley in Acta Physiologica Scandinavica
- Vol. 118 (2), 125-134
- https://doi.org/10.1111/j.1748-1716.1983.tb07252.x
Abstract
The kinetics of the TEA [tetraethylammonium chloride] and 4-AP [4-aminopyridine] sensitive K+ current (IK) in the slowly adapting lobster stretch receptor neuron were investigated in sub- and near-threshold voltage regions using electrophysiological and pharmacological techniques. In dynamic conditions, IK displayed fast and slow reactions. These were attributed to a Hodgkin-Huxley type of K activation and a slow type of K inactivation, respectively. The slow inactivation was unrelated to K+ flux dependent changes in intra- and pericellular K+ concentrations. Its stationary voltage dependence was shifted in a depolarizing direction by increasing and in a hyperpolarizing direction by decreasing the extracellular Ca2+ concentration. Based on these findings and its kinetic properties, the slow K inactivation was classified as a genuine channel gating process. The process of K activation was too fast for a dynamic analysis with the recording technique available. An estimate of its stationary voltage dependence was obtained in a voltage range from .apprx. -100 to .apprx. -40 mV. These observations were used in the formulation of a mathematical model describing the kinetic behavior of IK in the present preparation based on constant field and state transition theories.Keywords
This publication has 26 references indexed in Scilit:
- Intracellular ion control in lobster stretch receptor neuroneActa Physiologica Scandinavica, 1983
- Extracellular potassium accumulation in voltage‐clamped frog ventricular muscle.The Journal of Physiology, 1979
- Depletion and accumulation of potassium in the extracellular clefts of cardiac Purkinje fibers during voltage clamp hyperpolarization and depolarizationPflügers Archiv - European Journal of Physiology, 1977
- Does phospholipid flip-flop affect axon potassium channels?Biophysical Journal, 1975
- The Effect of Calcium on the Potassium Permeability in the Myelinated Nerve Fibre of Xenopus LaevisActa Physiologica Scandinavica, 1972
- Inward and delayed outward membrane currents in isolated neural somata under voltage clampThe Journal of Physiology, 1971
- Slow Changes of Potassium Permeability in the Squid Giant AxonBiophysical Journal, 1966
- The action potential in the myelinated nerve fibre of Xenopus laevis as computed on the basis of voltage clamp dataThe Journal of Physiology, 1964
- A quantitative description of potassium currents in myelinated nerve fibres of Xenopus laevisThe Journal of Physiology, 1963
- The after‐effects of impulses in the giant nerve fibres of LoligoThe Journal of Physiology, 1956