[Electrophysiological effects of ketamine on Ca(2+)-activated K+ channel in single rabbit portal vein cell].
The effects of ketamine on Ca(2+)-activated K+ channel currents were studied in dispersed single smooth muscle cells from rabbit portal vein using inside-out patch clamp technique. In a near physiological K+ and Ca2+ gradient, three populations of outward rectangular single currents were recorded in isolated cell membrane of rabbit portal vein at +60 mV membrane potential. These currents were judged as Ca(2+)-activated K+ channel currents since application of EGTA or Apamin in the internal solution inhibited these currents. Application of 10(-5)M or 10(-4)M ketamine inhibited the number of occurrences of channel opening and decreased open times, but did not reduce the amplitudes. When the 10(-3)M ketamine was applied, the Ca(2+)-activated K+ channel currents were abolished. We suggest that the depression of Ca(2+)-activated K+ channel currents may explain the continuous contraction observed in rabbit portal vein at a clinical concentration of ketamine from a point of electrophysiological K+ current study.
Yamazaki
M
M
Department of Anesthesiology, Toyama Medical and Pharmaceutical University.
Ito
Y
Y
Hatakeyama
N
N
Masuda
A
A
Shibuya
N
N
Momose
Y
Y
D000818:Animals; D002118:Calcium / Q000494:pharmacology* / Q000502:physiology; D004594:Electrophysiology; D007649:Ketamine / Q000494:pharmacology*; D009131:Muscle, Smooth, Vascular / Q000166:cytology*; D011169:Portal Vein; D015221:Potassium Channels / Q000187:drug effects* / Q000502:physiology; D011817:Rabbits
D015221:Potassium Channels; D007649:Ketamine; D002118:Calcium