ABSTRACT
AIM To investigate the effect of ke tamine on ATP-sensitive K + currents (I K ATP ) in single airway smooth muscle (ASM) cells of asthmatic rat. METHODS Single ASM cells of asthmatic rat were isolated with enzymatic dissociation technique. Effect of ketamine on I K ATP in single ASM cells was studied using the whole-cell configu ration of patch clamp technique. RESULTS Ketamine opened the ATP -sensitive K + channel (K ATP channel) in a dose-dependent manner. When the concentrations of ketamine were 1?10 -7 ,1?10 -6 ,1?10 -5 and 1?10 -4 mol?L -1 , the amplitude values of I K ATP were increased to 63 86?19 33 pA/pF(n=8,P
ABSTRACT
Objective To investigate the effect of carboxymethyl chitosan on ATP-sensitive K+ currents(IKATP) in single ventricular myocyte of rat.Methods Single ventricular myocyte of rat was isolated with enzymatic dissociation technique.Whole-cell patch clamp technique was used.The stimulating protocol was:holding potential-40 mV,command potential-100 mV to +50 mV,step potential + 10 mV,duration 200 ms,stimulating interval 6 s.Results Carboxymethyl chitosan inhibited the ATP-sensitive K+ channel(KATP channel) in a dose-dependent manner.When holding potential was-60 mV and stimulating potential was + 50 mV,carboxymethyl chitosan(0.1%,0.2%,0.3%) decreased the amplitude values of IKATP to 66.1%?9.9%,50.3%?13.3%and 39.8%?9.5%(n=7)of control,respectively.The changes of IKATP under other command potentials were consistent with this.Conclusion Carboxymethyl chitosan inhibits KATP channel in single ventricular myocyte of rat in a dose-dependent manner,and may be one of the mechanisms of antiarrhythmia.
ABSTRACT
AIM To investigate the effect of N methyl berbamine(NMB)on ATP sensitive potassium currents( I KATP )in single ventricular myocytes of guinea pig. METHODS Patch clamp technique with whole cell configuration. Holding potential was -40 mV, commanding potential was -100～+50 mV and duration was 600 ms. Pipette solution contained 0 3 mmol?L -1 ATP. RESULTS NMB inhibited I KATP in a concentration dependent manner. When holding potential was -40 mV and command potential was 0 mV, I KATP were reduced from (0 46?0 09) nA, (0 43?0 15) nA, and(0 47?0 10) nA to (0 37?0 07) nA( n=4,P