6533b86dfe1ef96bd12ca9b3
RESEARCH PRODUCT
Analysis of the hyperpolarizing effects of forskolin in guinea-pig atrial heart muscle.
Hermann NawrathOnkar TripathiFriederike HartungJuan L. Encinasubject
medicine.medical_specialtyBarium CompoundsGuinea PigsDiaphragm pumpIn Vitro TechniquesMembrane PotentialsGuinea pigchemistry.chemical_compoundChloridesInternal medicinemedicineRepolarizationAnimalsPharmacologyForskolinMyocardiumColforsinHeartGeneral MedicineHyperpolarization (biology)RubidiumResting potentialElectrophysiologyAtropineEndocrinologychemistryBariumRubidium Radioisotopesmedicine.drugdescription
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.
| year | journal | country | edition | language |
|---|---|---|---|---|
| 1988-04-01 | Naunyn-Schmiedeberg's archives of pharmacology |