A potassium ion diffusion potential causes adrenaline uptake in chromaffin-granule 'ghosts'.
Membrane vesicles ('ghosts') formed from bovine chromaffin granules accumulate adrenaline in response to a diffusion potential produced by adding K+ in the presence of valinomycin. This uptake occurs as a short (2--5 min) burst because of the transient nature of the diffusion potential. The potential-driven uptake is optimal at pH approximately 7.2, is inhibited by reserpine, and has an initial rate comparable with that of ATP-driven uptake. These results show that ATP-dependent adrenaline uptake may occur at least partly in response to the membrane potential generated by an electrogenic proton-translocating adenosine triphosphatase found in chromaffin-granule membranes.
D000818:Animals; D002417:Cattle; D002462:Cell Membrane / Q000187:drug effects / Q000378:metabolism; D002837:Chromaffin Granules / Q000378:metabolism*; D002838:Chromaffin System / Q000378:metabolism*; D004058:Diffusion; D004837:Epinephrine / Q000378:metabolism*; D066298:In Vitro Techniques; D008564:Membrane Potentials / Q000187:drug effects; D011188:Potassium / Q000378:metabolism* / Q000502:physiology; D012110:Reserpine / Q000494:pharmacology; D013050:Spectrometry, Fluorescence; D014634:Valinomycin / Q000494:pharmacology
D014634:Valinomycin; D012110:Reserpine; D011188:Potassium; D004837:Epinephrine