[3H] N-methyl-4-phenylpyridinium ion (MPP+) binds with a fully reversible, high affinity process to a population of sites mainly localized in the mouse striatum (B(max) = 168 ± 15 fmol/mg protein, K(D) = 1.4 ± 0.4 nM). The majority of specifically-bound radioactivity was localized in the synaptosomal fraction. Unilateral, striatal denervation with 6-hydroxydopamine (6-OHDA) markedly (by 65-70%) decreased the number of [3H]MPP+ sites. Besides dopamine, the vesicular markers tyramine, tetrabenazine and reserpine inhibited [3H]MPP+, while mazindol was a poor displacer. Adenosine triphosphate (ATP) and Mg2+-ions did not affect [3H]MPP+ binding. It is concluded that these sites may represent a marker of striatal storage vesicles for dopamine.
Characterization of a putatively vesicular binding site for 3H-MPP+ in mouse striatal membranes
DEL ZOMPO, MARIA;
1992-01-01
Abstract
[3H] N-methyl-4-phenylpyridinium ion (MPP+) binds with a fully reversible, high affinity process to a population of sites mainly localized in the mouse striatum (B(max) = 168 ± 15 fmol/mg protein, K(D) = 1.4 ± 0.4 nM). The majority of specifically-bound radioactivity was localized in the synaptosomal fraction. Unilateral, striatal denervation with 6-hydroxydopamine (6-OHDA) markedly (by 65-70%) decreased the number of [3H]MPP+ sites. Besides dopamine, the vesicular markers tyramine, tetrabenazine and reserpine inhibited [3H]MPP+, while mazindol was a poor displacer. Adenosine triphosphate (ATP) and Mg2+-ions did not affect [3H]MPP+ binding. It is concluded that these sites may represent a marker of striatal storage vesicles for dopamine.
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