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Synthesis and in vivo distribution in the rat of a dopamine agonist: N-([11C]methyl)norapomorphine

1993; Elsevier BV; Volume: 20; Issue: 1 Linguagem: Inglês

10.1016/0969-8051(93)90131-d

1872-9614

S. Zijlstra, Henk van der Worp, T. Wiegman, Gerben M. Visser, Jakob Korf, Willem Vaalburg,

Pharmacological Receptor Mechanisms and Effects

A method for the rapid production and purification of 10,11-dihydroxy-N-([11C]methyl)norapomorphine ([11C]APO), a dopamine agonist (DA), is described. The potency of this ligand for studying the D2-receptors was examined. The label was introduced by N-methylation of norapomorphine hydrobromide with no-carrier-added (n.c.a) [11C]CH3I, produced from cyclotron-produced [11C]carbon dioxide. In 60 min (EOB) a radiochemical yield of 15% (corrected for decay) was achieved, based on [11C]CH3I. The specific activity ranged from 5 to 11 GBq/μmol. The distribution, after intravenous injection, was studied in rats. The radioactivity level in the striatum was higher than in the cerebellum and frontal cortex and was decreased after D2-blockade. The highest uptake ratio (1.47) was found at 30 min after injection. Dopamine depletion with reserpine did increase the striatumcerebellum ratio at a low dosage of [11C]APO (10 nmol/kg). High uptakes of [11C]apomorphine were found in the lungs, liver and kidneys.