Vesicular Monoamine Transporter in Microvesicles from Bovine Posterior Pituitaries Is Immunologically Similar to But Distinct from the Chromaffin Granule Counterpart in Its Sensitivities to 1-Methyl-4-Phenylpyridinium and Histamine

Abstract

The microvesicles (MVs) in bovine posterior pituitaries contain the reserpine-sensitive vesicular monoamine transporter (Moriyama et al. (1995) J. Biol. Chem. 270, 11424–11429). An antibody against the N-terminal region of the monoamine transporter from bovine chromaffin granules recognized a polypeptide in the MVs with a similar molecular mass to the chromaffin granule counterpart. 1-Methyl-4-phenylpyridinium inhibited the norepinephrine uptake by the MVs and chromaffin vesicles, the concentrations required for 50% inhibition being 8 and 150 μM, respectively. Histamine also showed similar effect. These results indicated that the monoamine transporter in MVs is immunologically similar to, but distinguishable pharmacologically, from the chromaffin granule counterpart, and suggested the polymorphism of the transporter in bovine tissues.