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EFFECTS OF ELECTRICAL STIMULATION OF THE NIGROSTRIATAL PATHWAY OF THE RAT ON DOPAMINE METABOLISM
Author(s) -
Korf J.,
Grasdijk L.,
Westerink B. H. C.
Publication year - 1976
Publication title -
journal of neurochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.75
H-Index - 229
eISSN - 1471-4159
pISSN - 0022-3042
DOI - 10.1111/j.1471-4159.1976.tb01514.x
Subject(s) - homovanillic acid , dopamine , dopaminergic , nomifensine , chemistry , apomorphine , endocrinology , medicine , 3,4 dihydroxyphenylacetic acid , stimulation , nigrostriatal pathway , reuptake , probenecid , striatum , catecholamine , substantia nigra , biology , biochemistry , serotonin , receptor
— Electrical stimulation of the nigrostriatal dopaminergic pathway in rat brain elicited a frequency and current intensity‐dependent increased in the formation of homovanillic acid in the basal ganglia. The accumulation of the acid in probenecid‐treated animals was constant over 1 h, when maximally stimulated at 25 Hz and 300 μA. Dopamine levels remained unchanged during stimulation. When prior to stimulation the inhibitor of catecholamine synthesis α‐methyl‐ p ‐tyrosine methyl ester was administered, dopamine levels declined biphasically. Tyrosine and nomifensine, a dopamine uptake inhibitor, and apomorphine had no major effect on the formation of homovanillic acid, whilst α‐methyl‐ p ‐tyrosine prevented its formation. Our data suggest that dopamine in the striatum is compartmentalized and that the newly‐synthesized amine is released and converted to homovanillic acid. Apomorphine decreases dopamine flux only when dopaminergic neurons are at rest. When depolarized neither access of the precursor nor reuptake seem to influence the conversion of dopamine to homovanillic acid.