Abstract
Blocking action of Na channels by QX-314, a quaternary derivative of lidocaine, was studied in internally perfused and voltage-clamped axons of squid. In axons with intact Na inactivation, QX-314 exhibited both a frequency- and a voltage-dependent block of Na channels. Repetitive pulsing to more positive potentials enhanced the degree of block. Both frequency- and voltage-dependent blocks disappeared in axons in which Na inactivation had been destroyed by either pronase or N-bromoacetamide treatment. These results support the notion that Na inactivation not only modulates the frequency-dependent block but also involves the voltage-dependent binding reaction between QX-314 and Na channels.
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Selected References
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- Armstrong C. M., Bezanilla F., Rojas E. Destruction of sodium conductance inactivation in squid axons perfused with pronase. J Gen Physiol. 1973 Oct;62(4):375–391. doi: 10.1085/jgp.62.4.375. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Courtney K. R. Mechanism of frequency-dependent inhibition of sodium currents in frog myelinated nerve by the lidocaine derivative GEA. J Pharmacol Exp Ther. 1975 Nov;195(2):225–236. [PubMed] [Google Scholar]
- HODGKIN A. L., HUXLEY A. F. The dual effect of membrane potential on sodium conductance in the giant axon of Loligo. J Physiol. 1952 Apr;116(4):497–506. doi: 10.1113/jphysiol.1952.sp004719. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Hille B. Local anesthetics: hydrophilic and hydrophobic pathways for the drug-receptor reaction. J Gen Physiol. 1977 Apr;69(4):497–515. doi: 10.1085/jgp.69.4.497. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Rojas E., Rudy B. Destruction of the sodium conductance inactivation by a specific protease in perfused nerve fibres from Loligo. J Physiol. 1976 Nov;262(2):501–531. doi: 10.1113/jphysiol.1976.sp011608. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Strichartz G. R. The inhibition of sodium currents in myelinated nerve by quaternary derivatives of lidocaine. J Gen Physiol. 1973 Jul;62(1):37–57. doi: 10.1085/jgp.62.1.37. [DOI] [PMC free article] [PubMed] [Google Scholar]
- TAYLOR R. E. Effect of procaine on electrical properties of squid axon membrane. Am J Physiol. 1959 May;196(5):1071–1078. doi: 10.1152/ajplegacy.1959.196.5.1071. [DOI] [PubMed] [Google Scholar]
- Wu C. H., Narahashi T. Mechanism of action of propranolol on squid axon membranes. J Pharmacol Exp Ther. 1973 Jan;184(1):155–162. [PubMed] [Google Scholar]