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Reserpine as a competitive and reversible inhibitor of the catecholamine transporter of bovine chromaffin granules
Author(s) -
Kanner Baruch I.,
Fishkes Hanna,
Maron Ron,
Sharon Ilana,
Schuldiner Shimon
Publication year - 1979
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(79)81158-8
Subject(s) - hebrew , medical school , medicine , classics , history , medical education
The catecholamine-rich organelles of adrenal medulla, the chromaffin granules, are involved in transport, storage and secretion of these biogenic amines [l-4]. The isolated granules catalyse the uptake of large amounts of adrenaline and other biogenic amines by an ATP-dependent [5], uncoupler-sensitive [6] process. The granules have been found to contain a membrane-bound ATPase [7-lo]. The latter enzyme has been shown to translocate protons and to create an electrochemical proton gradient [ 1 l-161. Moreover, indirect evidence has been obtained for the involvement of the pH gradient (ApH) component [ 141 as well as the membrane potential (A$) component of this gradient [ 171 in amine transport. The ability to drive amine transport by artificially imposed pH gradients (acidic inside) provides direct evidence for the participation of at least ApH as an immediate driving force for the process [ 18,191. The ability of the granules [5] and isolated granule membrane vesicles [20] to accumulate various biogenic amines, as well as the mutual inhibition on transport of the amines [5] suggests the presence of a single carrier with a rather broad specificity. This may also serve to explain the inhibitory action of reserpine which also has been reported to act as a competitive inhibitor of the transport process [21]. In apparent contrast to this observation is the reported irreversibility of this drug (cf. [22]). Using isolated membranes lacking endogenous amines, we provide here additional evidence for a single