Effects of volatile anesthetic isoflurane on ATP-sensitive K+ channels in rabbit ventricular myocytes.
It has been suggested that volatile anesthetic, isoflurane mediates cardioprotective effects via activation of the ATP-sensitive K+ (KATP) channels. However, no direct evidence has been provided to define whether isoflurane activates cardiac KATP channels using patch-clamp technique. We examined the effects of isoflurane on the KATP channels in rabbit ventricular myocytes by use of patch-clamp technique. Contrary to the results of the in vivo experiments, isoflurane inhibited the channel activity without a change in the single-channel conductance. Isoflurane decreased the channel activity by a decrease in burst duration and an increase in the inter-burst duration. On the other hand, isoflurane diminished the ATP sensitivity of KATP channels, indicating an increased probability of KATP channel opening for a given concentration of ATP after isoflurane anesthesia. The result supports, at least in part, the hypothesis that isoflurane mediates cardioprotective effects via KATP channel activation.
Han
J
J
Department of Physiology and Biophysics, Inje University, Pusan, Korea.
Kim
E
E
Ho
W K
WK
Earm
Y E
YE
D018685:Anesthetics, Inhalation / Q000494:pharmacology*; D000818:Animals; D006352:Heart Ventricles / Q000378:metabolism*; D015640:Ion Channel Gating / Q000187:drug effects; D007530:Isoflurane / Q000494:pharmacology*; D018408:Patch-Clamp Techniques; D015221:Potassium Channels / Q000187:drug effects*; D011817:Rabbits
D018685:Anesthetics, Inhalation; D015221:Potassium Channels; D007530:Isoflurane