ISSN:
1432-1912
Keywords:
AN-132
;
Lidocaine
;
Voltage clamp
;
Na current
;
Ca current
Source:
Springer Online Journal Archives 1860-2000
Topics:
Medicine
Notes:
Summary We studied the effects of AN-132 (10, 30 and 100 μmol/1), an analogue of lidocaine, on membrane currents and action potentials of single guinea-pig ventricular cells using whole-cell clamp techniques. The effects of lidocaine, an authentic class I antiarrhythmic agent were used for comparative purposes. (1) AN-132 decreased the Na current (I Na) in a concentration-dependent manner, with a greater efficacy than seen with lidocaine. The concentration of the half maximal inhibition on I Na (K d) was (31.7 μmol/1), for AN-132 and 94.9 μmol/l for lidocaine. (2) AN-132 also decreased the Ca current (I Ca), concentration-dependently, while lidocaine had only a minor effect on I Ca. The half maximal inhibition on I Ca (K d) was 23.1 μmol/l and 27.4 μmol/l for AN-132 and lidocaine, respectively. (3) AN-132 decreased the I K1, in a concentration-dependent manner; lidocaine was without effect. (4) AN-132 increased the unspecified steady state outward current, at positive potentials and depressed the time- and voltage-dependent outward K current (I K). Lidocaine had no effect on either current. (5) AN-132 shortened the action potential duration (APD), in a concentration-dependent manner, without altering the resting potential. From these findings, we conclude that apart from a potent inhibitory effect on I Na, AN-132 had a variety of effects on other currents, properties not shared by lidocaine. Such multiple blocking effects on the membrane currents may relate to the alleged potent antiarrhythmic effect of AN-132.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00165147
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