Effects of volatile anaesthetics on a high conductance calcium dependent potassium channel in cultured hippocampal neurons.
(1) The effects of isoflurane and halothane (at nominal concentrations of 4%) were studied on a high conductance Ca2+-dependent K+ channel using inside-out patches from cultured rat hippocampal neurons. (2) With physiological-like concentrations of K+ across patches (140 mM internal and 5 mM external), unitary activity from a 4 pA channel (conductance near 100 pS) was evident in excised patches. (3) Isoflurane or halothane had no effects on unitary properties of K (Ca) including channel amplitudes and open and closed times. The channel open probability was also unchanged in the presence of the volatile agent. The results suggest that macroscopic high conductance K (Ca) currents in hippocampal neurons would be relatively insensitive to high concentrations of inhalational anaesthetics.
McLarnon
J
J
Department of Pharmacology and Therapeutics, Faculty of Medicine, The University of British Columbia, Vancouver, Canada. McLarnon@unixg.ubc.ca
Sawyer
D
D
D018685:Anesthetics, Inhalation / Q000494:pharmacology*; D000818:Animals; D002118:Calcium / Q000502:physiology*; D002478:Cells, Cultured; D006221:Halothane / Q000494:pharmacology; D006624:Hippocampus / Q000166:cytology* / Q000187:drug effects; D007530:Isoflurane / Q000494:pharmacology; D009474:Neurons / Q000187:drug effects / Q000378:metabolism*; D018408:Patch-Clamp Techniques; D015221:Potassium Channels / Q000187:drug effects*; D051381:Rats
D018685:Anesthetics, Inhalation; D015221:Potassium Channels; D007530:Isoflurane; D002118:Calcium; D006221:Halothane