TY - JOUR T1 - REGIONAL DISTRIBUTION AND METABOLISM OF H<sup>3</sup>-TYRAMINE IN THE RAT BRAIN JF - Journal of Pharmacology and Experimental Therapeutics JO - J Pharmacol Exp Ther SP - 196 LP - 204 VL - 171 IS - 2 AU - MENEK GOLDSTEIN AU - BERTA ANAGNOSTE AU - AKIKO YAMAMOTO AU - WILLIAM C. FELCH, JR. Y1 - 1970/02/01 UR - http://jpet.aspetjournals.org/content/171/2/196.abstract N2 - The disposition and metabolism of H3-tyramine was investigated in different regions of the central nervous system after the intraventricular injection of the labeled amine. The hypothalamus contained the highest concentration of radioactive amines. The ratio of amines to acidic-neutral metabolites was higher in the hypothalamus than in other analyzed regions of the brain. In all analyzed regions of the central nervous system, with the exception of the striatum, the major part of the radioactivity of the amine fraction was associated with H3-octopamine. In the striatum all the radioactivity of the amine fraction was associated with unchanged H3-tyramine. The deaminated H3-metabolites of tyramine were isolated and identified in different regions of the brain. The major metabolite in all analyzed regions was found to be H3-p-hydroxyphenylacetic acid and the minor was found to be H3-p-hydroxyphenylethanol. Although both H3-phydroxyphenylacetic acid and H3-p-hydroxyphenylethanol were present in the conjugated form, the percentage of the latter in this form was greater. The ratio of conjugated to nonconjugated metabolites increased with time after administration of H3-tyramine. No evidence was obtained for the presence of deaminated metabolites from H3-octopamine newly formed from H3-tyramine. After inhibition of monoamine oxidase by pheniprazine there was a several-fold increase of the radioactivity in the H3-amine fraction concomitant with a decrease in the concentration of the deaminated H3-metabolites. Inhibition of dopamine-β-hydroxylase with disulfiram prevents the conversion of H3-tyramine to H3-octopamine, and after monoamine oxidase and dopamine-β-hydroxylase inhibition, H3-tyramine accumulates in all H3-octopamine-containing regions of the brain. © 1970, by The Williams &amp; Wilkins Co. ER -