Effects of ropivacaine on sodium, calcium, and potassium currents in guinea pig ventricular myocytes.
Abstract
AIM: To study the effects of ropivacaine (Rop) on sodium current (INa), L-type
calcium current (ICa-L), inward rectifier potassium current (IK1), and delayed
rectifier potassium current (IK) in isolated guinea pig ventricular myocytes.
METHODS: Whole cell patch-clamp techniques were used in our experiment.
RESULTS: At potential of -40 mV, Rop 10, 50, and 100 micromol/L decreased sodium
current by 8.3 %, 33.3 %, and 62.5 %, respectively and prolonged the time
constant of INa inactivation by 8.2 %, 24.7 %, and 64.4 %, respectively (n = 5
cells from 3 animals, P < 0.05). At potential of +10 mV, Rop 50 and 100
micromol/L decreased L-type calcium current by 7.6 % and 22.5 %, and prolonged
the slow time constant of ICa-L inactivation by 15.5 % and 33.0 %, respectively
(n = 5 cells from 4 animals, P < 0.05). Rop 50 and 100 micromol/L did not
markedly change the peak current of delayed rectifier potassium current and
inward rectifier potassium current (n = 5 cells from 3 animals, P > 0.05),
respectively.
CONCLUSION: Rop depressed INa and ICa-L, which may be related to its cardiotoxic
effect.
Keywords:
calcium current (ICa-L), inward rectifier potassium current (IK1), and delayed
rectifier potassium current (IK) in isolated guinea pig ventricular myocytes.
METHODS: Whole cell patch-clamp techniques were used in our experiment.
RESULTS: At potential of -40 mV, Rop 10, 50, and 100 micromol/L decreased sodium
current by 8.3 %, 33.3 %, and 62.5 %, respectively and prolonged the time
constant of INa inactivation by 8.2 %, 24.7 %, and 64.4 %, respectively (n = 5
cells from 3 animals, P < 0.05). At potential of +10 mV, Rop 50 and 100
micromol/L decreased L-type calcium current by 7.6 % and 22.5 %, and prolonged
the slow time constant of ICa-L inactivation by 15.5 % and 33.0 %, respectively
(n = 5 cells from 4 animals, P < 0.05). Rop 50 and 100 micromol/L did not
markedly change the peak current of delayed rectifier potassium current and
inward rectifier potassium current (n = 5 cells from 3 animals, P > 0.05),
respectively.
CONCLUSION: Rop depressed INa and ICa-L, which may be related to its cardiotoxic
effect.