Saxitoxin and procaine act independently on separate sites of the sodium channel
- 1 January 1976
- journal article
- research article
- Published by Springer Nature in Pflügers Archiv - European Journal of Physiology
- Vol. 364 (1), 65-70
- https://doi.org/10.1007/bf01062913
Abstract
Voltage clamp experiments were done on single myelinated nerve fibres of the frog,Rana esculenta. The time course of procaine action (1.0 mM at pH 7.2) was obtained from changes inI Na on changing solutions during repetitive (1 Hz) depolarizing pulses of constant amplitude following hyperpolarizing prepulses. The mean half times of onset and offset of procaine block were 3.7 and 28 s, respectively. In the presence of 1.4 nM saxitoxin (STX) the corresponding times were virtually the same, 3.1 and 27 s. Similarly, the time course of partial relief from procaine block that is obtained by increasing the frequency of the prepulse-test pulse pairs from 1–10 Hz was unaffected in the presence of STX. Comparison of the equilibrium effects of procaine concentrations ranging from 0.03–1.0 mM suggest a one-to-one drug-receptor reaction. The fraction of Na channels blocked at equilibrium with 1.0 mM procaine, 1.4 nM STX, and 1.0 mM procaine + 1.4 nM STX was 0.81, 0.49, and 0.90, respectively. This result and the kinetic behaviour fully agree with the idea of two separate and independent receptors for procaine and STX.This publication has 16 references indexed in Scilit:
- Different Sites of Membrane Action for Tetrodotoxin and Lipid-Soluble AnestheticsCanadian Journal of Physiology and Pharmacology, 1975
- The receptor for tetrodotoxin and saxitoxin. A structural hypothesisBiophysical Journal, 1975
- The rates of saxitoxin action and of saxitoxin-tetrodotoxin interaction at the node of RanvierPflügers Archiv - European Journal of Physiology, 1975
- Local Anesthetics: Effects on Permeability Properties of Nodal Membrane in Myelinated Nerve Fibres from Xenopus. Potential Clamp ExperimentsActa Physiologica Scandinavica, 1974
- The binding of labelled saxitoxin to the sodium channels in nerve membranesThe Journal of Physiology, 1973
- The rate of action of tetrodotoxin on myelinated nerve fibres of Xenopus laevis and Rana esculentaThe Journal of Physiology, 1973
- The Inhibition of Sodium Currents in Myelinated Nerve by Quaternary Derivatives of LidocaineThe Journal of general physiology, 1973
- Partial Characterization of a Tetrodotoxin-Binding Component from Nerve MembraneProceedings of the National Academy of Sciences, 1972
- A new voltage clamp method for Ranvier nodesPflügers Archiv - European Journal of Physiology, 1969
- Hydrolysis of Procaine in Aqueous Buffer SolutionsActa Pharmacologica et Toxicologica, 1949