Hydroxytryptamine transport by the bovine chromaffin-granule membrane.
5-Hydroxytryptamine is accumulated by resealed chromaffin-granule 'ghosts' if a pH gradient (acid inside) is imposed across their membranes by preincubating them at low pH. This uptake, like that driven by MgATP, is reserpine- and uncoupler-sensitive. This strongly suggests that catecholamines are taken up by intact granules in response to a pH gradient. In line with this, it is shown that 5-hydroxytryptamine decreases the pH gradient generated in the presence of MgATP, an effect that is inhibited by reserpine; nigericin, which discharges the pH gradient in the presence of K+, inhibits uptake. Permeant anions, however, also inhibit uptake. It is suggested that this may be because they permit equilibration of amine cations directly across the membrane, down concentration gradients.
D000818:Animals; D000838:Anions; D001692:Biological Transport / Q000187:drug effects; D002417:Cattle; D002837:Chromaffin Granules / Q000378:metabolism*; D002838:Chromaffin System / Q000378:metabolism*; D006863:Hydrogen-Ion Concentration; D066298:In Vitro Techniques; D008564:Membrane Potentials; D008566:Membranes / Q000378:metabolism; D011522:Protons; D012110:Reserpine / Q000494:pharmacology; D012701:Serotonin / Q000378:metabolism*; D012702:Serotonin Antagonists / Q000494:pharmacology
D000838:Anions; D011522:Protons; D012702:Serotonin Antagonists; D012701:Serotonin; D012110:Reserpine