Title: The effect of dihydroxyphenylalanine, pheniprazine and dextroamphetamine on the in vivo release of dopamine from the caudate nucleus.
Abstract: Changes in the amount of dopamine (DA) and dihydroxyphenylacetic acid (DOPAC) recovered in vivo from the caudate nucleus by means of push-pull cannulae were investigated before and after the systemic administration of dihydroxyphenylalanine (dopa) and topical administration of pheniprazine and dextroamphetamine. DA and DOPAC were determined fluorometrically after condensation with ethylenediamine and were identified further by thin-layer chromatography and parallel fluorometric assays. When Locke's solution was perfused, no significant amount (<1 ng/50 min) of DA appeared in the perfusate and 75 mg/kg of dopa i.v. did not increase DA output. A significant amount of DOPAC (21 ng/5O min) was recovered prior to dopa administration and this was increased 7-fold after dopa administration. Perfusion with 1 mg/ml of pheniprazine did not affect DA output but suppressed the increase in DOPAC after dopa administration. Perfusion with 0.5 mg/ml of dextroamphetamine resulted in a significant (12 ng/50 min) DA output which was increased further by dopa administration. it is apparent that normally almost all DA in the caudate nucleus is present in a nondiffusible form while all DOPAC is freely diffusible. Cellular reuptake, blocked by dextroamphetamine, is an important method of inactivation of synaptically released DA whereas monoamine oxidase has no such role.
Publication Year: 1968
Publication Date: 1968-08-01
Language: en
Type: article
Indexed In: ['pubmed']
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Cited By Count: 139
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