Additive potentiation by co-application of propofol and sevoflurane on GABA-induced chloride current in cultured neurons from rat dorsal root ganglia.
OBJECTIVE
To investigate the effects of various concentrations of sevoflurane and propofol and a combination of the two agents on chloride current induced by bath utilization of 3 x 10(-6) mol/L gamma-aminobutyric acid (GABA) in the rat dorsal root ganglia neurons maintained in primary culture.


METHODS
Sensory neurons from rat dorsal root ganglia were dissociated and cultured. The whole-cell patch clamp technique was used to record chloride current. All drugs were applied with a rapid perfusion system, named "Y-tube" method.


RESULTS
The peak chloride current amplitude was induced by 3 x 10(-6) mol/L GABA with substantially increasing of both sevoflurane and propofol. Additionally, desensitization of IGABA induced by either propofol or sevoflurane was not observed. We examined actions of various concentrations of propofol (3 x 10(-7), 1 x 10(-6), 3 x 10(-6) mol/L), sevoflurane (7 x 10(-4) mol/L) and their combination at concentrations relevant to clinical anesthesia on IGABA propofol (3 x 10(-7), 1 x 10(-6), 3 x 10(-6) mol/L) produced a concentration-dependent increase in the response to 3 x 10(-6) mol/L GABA on IGABA. When combined with 7 x 10(-4) mol/L sevoflurane, the potentiation of response to GABA obtained with various concentrations of propofol was not different from a theoretical additive response (P > 0.05).


CONCLUSIONS
Either sevoflurane or propofol and their combination at clinically relevant concentrations potentiate the GABA-induced chloride current, which may at least partially contribute to the anesthetic mechanism. Additive interaction obtained with a co-application of propofol and sevoflurane may provide an evidence for a clinical combination of these two anesthetic agents.
Luo
A
A
Department of Anesthesiology, Tongji Hospital, Tongji Medical University, Wuhan 430030, China.
Sugiyama
K
K
D018685:Anesthetics, Inhalation / Q000494:pharmacology*; D018686:Anesthetics, Intravenous / Q000494:pharmacology*; D000818:Animals; D000831:Animals, Newborn; D002478:Cells, Cultured; D018118:Chloride Channels / Q000187:drug effects / Q000378:metabolism*; D004357:Drug Synergism; D005727:Ganglia, Spinal / Q000166:cytology*; D008738:Methyl Ethers / Q000494:pharmacology*; D009474:Neurons / Q000166:cytology; D015742:Propofol / Q000494:pharmacology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D000077149:Sevoflurane; D005680:gamma-Aminobutyric Acid / Q000494:pharmacology*
D018685:Anesthetics, Inhalation; D018686:Anesthetics, Intravenous; D018118:Chloride Channels; D008738:Methyl Ethers; D000077149:Sevoflurane; D005680:gamma-Aminobutyric Acid; D015742:Propofol