Dopaminergic neurons: effects of electrical stimulation on dopamine biosynthesis
Murrin, L.C.; Roth, R.H.
Molecular Pharmacology 12(3): 463-475
1976
ISSN/ISBN: 0026-895X PMID: 934059 Document Number: 109289
Electrical stimulation of the medial forebrain bundle was employed to study the effects of increased impulse flow on dopamine synthesis. Stimulation at frequencies ranging from 5 to 30 Hz resulted in an increase in the specific activity of dopamine isolated from the neostriatum 20 min after i.v. administration of [3]tyrosine. The optimal frequency for this effect was 15 Hz. Similar results were found in the olfactory tubercles. Phenylalanine was also a precursor for neostriatal dopamine. The increase in neostriatal dopamine specific activity following labeled precursor administration continued for 15 min after stimulation. About 99% of the total fraction of labeled catecholamines found in the neostriatum 20 min following tyrosine administration was identified as dopamine by Amberlite CG-120 column chromatography. Dopa accumulation following dopa decarboxylase inhibition was also increased by electrical stimulation. This increased accumulation of dopa continued for at least 15 min after stimulation. The ability of increased impulse flow to increase dopamine synthesis by altering the activity of tyrosine hydroxylase in dopaminergic neurons is discussed.