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. 1993 Apr;108(4):865–869. doi: 10.1111/j.1476-5381.1993.tb13479.x

Fendiline inhibits L-type calcium channels in guinea-pig ventricular myocytes: a whole-cell patch-clamp study.

O Tripathi 1, W Schreibmayer 1, H A Tritthart 1
PMCID: PMC1908174  PMID: 8485628

Abstract

1. Fendiline, a diphenylalkylamine type of antianginal drug, was examined for its effects on L-type calcium channels in guinea-pig ventricular myocytes by the whole-cell patch-clamp technique. 2. Fendiline (0.3-100 microM) applied extracellularly inhibited the calcium channel current (ICa) in a concentration- and time-dependent manner. The IC50 of fendiline was 17.0 +/- 2.43 microM and the Hill slope was 1.39 +/- 0.23. 3. Inhibition of ICa by fendiline appeared with an onset of less than 3 s. 4. Fendiline inhibited ICa at all the membrane potentials tested and shifted the current-voltage curve upwards. The overall calcium channel conductance (gCa) of the cell was reduced and conductance-voltage curve was shifted to the left in the presence of fendiline. 5. Isoprenaline (0.5-1 microM), a beta-adrenoceptor agonist, partially reversed the inhibitory effect of fendiline on ICa. 6. It is suggested that fendiline applied extracellularly blocks L-type calcium channels and reduces calcium channel conductance of the cell. The calcium channels thus inhibited are, nevertheless, still available for beta-adrenoceptor stimulation.

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Selected References

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