Summary
The effects of forskolin on action potential configuration and on both uptake and efflux of 86Rb+ were studied in guinea-pig left atria. The action potential was prolonged by forskolin in the plateau range but shortened at the end of repolarization; maximal upstroke velocity and amplitude of slow response potentials were enhanced. In partially depolarized preparations, the resting potential was increased by forskolin; this effect was not prevented by atropine 1 μmol/1. Forskolin augmented the rate constant of 86Rb+ efflux in beating and in resting preparations. The uptake of 86Rbs+ was enhanced by forskolin in resting preparations. It is concluded that forskolin stimulates the Na+, K+ -pump and activates a background potassium conductance. Both effects may account for the shortening effect of the drug on the action potential and the increase in resting potential seen in partially depolarized preparations.
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Encina, J.L., Hartung, F., Tripathi, O. et al. Analysis of the hyperpolarizing effects of forskolin in guinea-pig atrial heart muscle. Naunyn-Schmiedeberg's Arch Pharmacol 337, 435–439 (1988). https://doi.org/10.1007/BF00169536
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DOI: https://doi.org/10.1007/BF00169536