Paradoxical reversion of the inhibitory effects of dihydropyridine enantiomers on the calcium current in frog heart by CGP 28861

Article date: February 1989

By: Alexander Filippov, Evgeny Kobrinsky, Vladimir Porotikov, Maya Saxon in Volume 96, Issue 2, pages 253-255

A dihydropyridine CGP 28861 (5 × 10−6m) did not change slow inward Ca current as measured by the double sucrose gap method in frog atrial fibres but decreased the agonist effects of Bay K 8644, CGP 28392, (+m)−(S)−202–791 and the antagonist effects of nifedipine and (+m)−(PN)−200–110. Paradoxically, the weak antagonists (−)−(R)−202–791, (−)−(PN)−200–110 and (+)‐Bay K 8644 increased Ca‐current after washout of CGP 28861. These data suggest that CGP 28861 can convert the dihydropyridine Ca‐channel receptor from an antagonistic site into an agonistic one.

DOI: 10.1111/j.1476-5381.1989.tb11808.x

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