British Journal of Anaesthesia, 2002, Vol. 88, No. 6 864-866
© 2002 The Board of Management and Trustees of the British Journal of Anaesthesia
Short Communications |
Bupivacaine inhibits human neuronal Kv3 channels in SH-SY5Y human neuroblastoma cells
1Clinic of Anaesthesiology, University Hospital Eppendorf and Institute of Neural Signal Transduction, Centre for Molecular Neurobiology, University of Hamburg, Germany. 2Department of Anaesthesiology and Intensive Care Medicine, University of Bonn, Germany. 3Department of Anaesthesiology and Intensive Care Medicine, University of Bonn, Germany, and Departments of Anaesthesiology and Physiology, Weill Medical College of Cornell University, New York, NY, USA.*Corresponding author: Klinik für Anästhesiologie, Universitätsklinik Eppendorf, Martinistrasse 52, D-20246 Hamburg, Germany
Background. Information on molecular targets that may be involved in the neurotoxicity of bupivacaine is limited. Suppression of Kv3 channels has been demonstrated to result in abnormal patterns in the electroencephalogram and in seizures. Inhibition of Kv3 channels by bupivacaine may consequently contribute to its neuroexcitatory side-effects. Data on the effects of bupivacaine on these potassium channels are lacking. We therefore characterized the effects of bupivacaine on human Kv3 channels natively expressed in SH-SY5Y cells.
Methods. Kv3 channels natively expressed in human SH-SY5Y cells were studied using a standard whole-cell patch-clamp protocol.
Results. Bupivacaine reversibly inhibited Kv3 channels in a concentration-dependent manner. The half-maximal inhibitory concentration (IC50) for conductance block was 57 µM and the Hill coefficient was close to unity. Bupivacaine accelerated macroscopic current decline by inducing inactivation-like behaviour. The midpoint of current activation was shifted to depolarized potentials in a concentration-dependent and reversible manner by a maximum of 26 mV. The IC50 was 47 µM and the Hill coefficient was 2.4. The free arterial plasma concentrations of bupivacaine that have been estimated to occur during convulsions in man would inhibit the Kv3 channels by at least 40% and would shift the midpoint of current activation by a minimum of 9 mV.
Conclusions. Both inhibition of potassium channels and a depolarizing shift of their activation midpoint would increase neuronal excitability. The effects of bupivacaine on human Kv3 channels are thus compatible with a contributory role of Kv channel alteration in bupivacaine-induced neuronal excitation.
Br J Anaesth 2002; 88: 864–6
CiteULike 
Connotea 
Del.icio.us What's this?
This article has been cited by other articles:
|
|
 |
|
  M. A. Punke, T. Licher, O. Pongs, and P. Friederich Inhibition of Human TREK-1 Channels by Bupivacaine Anesth. Analg., June 1, 2003; 96(6): 1665 - 1673. [Abstract] [Full Text] [PDF]
|
|