Differences in the kinetics of dopamine uptake in synaptosome preparations of the median eminence relative to other dopaminergically innervated brain regions

L. Annunziato, P. Leblanc, C. Kordon, R. I. Weiner

Research output: Contribution to journalArticlepeer-review

Abstract

A comparison of the kinetics of dopamine uptake was made in synaptosomal preparations of the median eminence, striatum and olfactory tubercle. Double reciprocal Lineweaver-Burk plots of the initial velocity versus the concentration of dopamine yielded a single straight line in all three areas. The Michaelis constant (Km) in the median eminence (1.8 ± 0.9 x 10-6 M) was significantly higher (p <0.05) than in the striatum (4.2 ± 0.8 x 10-8 M) or olfactory tubercle (6.3 ± 1.9 x 10-8 M). Uptake in the median eminence appeared to be predominantly into dopaminergic terminals since preincubation with desipramine did not affect the maximum velocity (Vmax) of dopamine uptake. Observed uptake was predominantly due to transport across the neuronal membrane and not into storage granules, since reserpine only caused a small decrease in uptake. The low affinity of dopamine uptake in median eminence synaptosomes is consistent with the neurosecretory nature of these terminals, whereas, in the striatum and olfactory tubercle, high affinity reuptake is consistent with the role of dopamine as a neurotransmitter.

Original languageEnglish
Pages (from-to)316-320
Number of pages5
JournalNeuroendocrinology
Volume31
Issue number5
Publication statusPublished - 1980

ASJC Scopus subject areas

  • Endocrinology
  • Neuroscience(all)

Fingerprint Dive into the research topics of 'Differences in the kinetics of dopamine uptake in synaptosome preparations of the median eminence relative to other dopaminergically innervated brain regions'. Together they form a unique fingerprint.

Cite this