Elevation of dopamine D2 but not D1 receptors in adult rat neostriatum after neonatal 6-hydroxydopamine denervation

Brain Res. 1990 Dec 17;536(1-2):287-96. doi: 10.1016/0006-8993(90)90036-b.

Abstract

Monoamine levels and the binding properties of [3H]SCH23390, a D1-specific ligand, and [3H]raclopride, a D2-specific ligand, were measured in the rostal and caudal neostriatum to investigate the fate of dopamine receptors following bilateral cerebroventricular injection of 6-hydroxydopamine in 3-day-old rats. After survival times of 15, 30 or 90 days, measurement of monoamine levels and of [3H]SCH23390 binding were also obtained from the cerebral cortex. At all three survival times, dopamine content was reduced by more than 90% of control values in both the rostral and caudal neostriatum; in cerebral cortex, the dopamine depletion was less profound (80%) and noticeable only after 1 and 3 months. In the rostral but not the caudal neostriatum, serotonin and 5-hydroxyindoleacetic acid concentrations were markedly increased at 1 and 3 months; cortical serotonin also was augmented at 3 months. There were no changes in neostriatal [3H]SCH23390 binding at any of the survival times, but a transient elevation occurred in the cortex at 1 month. In the rostral but not the caudal neostriatum, [3H]raclopride binding showed a slight elevation at 1 month and a further, highly significant increase at 3 months. As measured in individual rats, this increase in [3H]raclopride binding was linearly correlated with the increase in serotonin turnover (ratio of 5-hydroxyindoleacetic acid/serotonin). Such an up-regulation of D2 receptors, restricted to the rostral neostriatum which was also the site of a serotonin hyperinnervation, was probably indicative of a serotonin control on the expression of D2 receptors after dopamine denervation.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Animals, Newborn / metabolism*
  • Biogenic Monoamines / metabolism
  • Caudate Nucleus / drug effects*
  • Caudate Nucleus / metabolism
  • Chromatography, High Pressure Liquid
  • Female
  • Gyrus Cinguli / metabolism
  • Hydroxydopamines / pharmacology*
  • Injections, Intraventricular
  • Oxidopamine
  • Putamen / drug effects*
  • Putamen / metabolism
  • Radioligand Assay
  • Rats
  • Rats, Inbred Strains
  • Receptors, Dopamine / drug effects*
  • Receptors, Dopamine / metabolism
  • Receptors, Dopamine D1
  • Receptors, Dopamine D2

Substances

  • Biogenic Monoamines
  • Hydroxydopamines
  • Receptors, Dopamine
  • Receptors, Dopamine D1
  • Receptors, Dopamine D2
  • Oxidopamine