Medizinische Universität Graz Austria/Österreich - Forschungsportal - Medical University of Graz
Gewählte Publikation:
Olschewski, A; Wolff, M; Bräu, ME; Hempelmann, G; Vogel, W; Safronov, BV.
Enhancement of delayed-rectifier potassium conductance by low concentrations of local anaesthetics in spinal sensory neurones.
BRIT J PHARMACOL 2002 136: 540-549.
Doi: 10.1038/sj.bjp.0704754
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- Führende Autor*innen der Med Uni Graz
- Olschewski Andrea
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- Abstract:
- 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. Bupivacaine, lidocaine and mepivacaine at low concentrations (1 - 100 microM) enhanced delayed-rectifier K(+) current in intact neurones within the spinal cord slice, while exhibiting a partial blocking effect at higher concentrations (>100 microM). In isolated somata 0.1 - 10 microM 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. 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. 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.
- Find related publications in this database (using NLM MeSH Indexing)
- Analysis of Variance -
- Anesthetics, Local - pharmacology
- Animals - pharmacology
- Bupivacaine - chemistry
- Delayed Rectifier Potassium Channels - chemistry
- Dose-Response Relationship, Drug - chemistry
- Electric Conductivity - chemistry
- In Vitro - chemistry
- Kinetics - chemistry
- Lidocaine - pharmacology
- Mepivacaine - pharmacology
- Neurons, Afferent - drug effects
- Patch-Clamp Techniques - drug effects
- Posterior Horn Cells - drug effects
- Potassium Channels - drug effects
- Potassium Channels, Voltage-Gated - drug effects
- Rats - drug effects
- Sodium Channels - drug effects
- Stereoisomerism - drug effects
- Find related publications in this database (Keywords)
- patch-clamp
- spinal cord
- local anaesthetics
- delayed rectifier potassium channel
- single channel