Effects of Quinine and Quinidine on the Transient Outward and on the L-Type Ca<sup>2+</sup> Current in Rat Ventricular Cardiomyocytes
説明
<jats:p>The effects of the enantiomers quinine and quinidine on the transient outward current (Ito) and on the L-type Ca2+ current (ICa) were investigated in rat ventricular cardiomyocytes using the patch-clamp technique. At a stimulation frequency of 2 Hz, both quinine and quinidine depressed the magnitude of Ito and ICa; the half-maximal effects on Ito were achieved at 11 and 15 µmol/l, respectively, and those on ICa at 14 and 10 µmol/l, respectively. At 0.2 Hz, both drugs depressed the magnitude of Ito, but not that of ICa. A change in extracellular pH from 7.3 to 8.3 did not significantly influence the effects of the drugs (which are protonated to 98% at pH 7.3) on Ito or ICa. It is concluded that neither the different chemical structure nor the amount of protonation of quinine and quinidine controls their effects on Ito or ICa.</jats:p>
収録刊行物
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- Pharmacology
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Pharmacology 65 (4), 187-192, 2002
S. Karger AG