Journal article

Publication year: 2002

Pages: 540-549

Journal: British Journal of Pharmacology

Volume number: 136

Issue number: 4

ISSN: 0007-1188

Open access status: Green

DOI Link: https://doi.org/10.1038/sj.bjp.0704754

Publisher: Wiley

Abstract: 

1 Combining the patch-clamp recordings in slice preparation with the 'entire soma isolation' method we studied action of several local anaesthetics on delayed-rectifier K+ currents in spinal dorsal horn neurones.

2 Bupivacaine, lidocaine and mepivacaine at low concentrations (1 - 100 muM) enhanced delayed-rectifier K+ current in intact neurones within the spinal cord slice, while exhibiting a partial blocking effect at higher concentrations (> 100 muM). In isolated somata 0.1 - 10 muM bupivacaine enhanced delayed-rectifier K+ current by shifting its steady-state activation characteristic and the voltage-dependence of the activation time constant to more negative potentials by 10-20 mV.

3 Detailed analysis has revealed that bupivacaine also increased the maximum delayed-rectifier K+ conductance by changing the open probability, rather than the unitary conductance, of the channel.

4 It is concluded that local anaesthetics show a dual effect on delayed-rectifier K+ currents by potentiating them at low concentrations and partially suppressing at high concentrations. The phenomenon observed demonstrated the complex action of local anaesthetics during spinal and epidural anaesthesia, which is not restricted to a suppression of Na+ conductance only.

Harvard Citation style: Olschewski, A., Wolff, M., Bräu, M., Hempelmann, G., Vogel, W. and Safronov, B. (2002) Enhancement of delayed-rectifier potassium conductance by low concentrations of local anaesthetics in spinal sensory neurones, British Journal of Pharmacology, 136(4), pp. 540-549. https://doi.org/10.1038/sj.bjp.0704754

APA Citation style: Olschewski, A., Wolff, M., Bräu, M., Hempelmann, G., Vogel, W., & Safronov, B. (2002). Enhancement of delayed-rectifier potassium conductance by low concentrations of local anaesthetics in spinal sensory neurones. British Journal of Pharmacology. 136(4), 540-549. https://doi.org/10.1038/sj.bjp.0704754