Desensitized D2 autoreceptors are resistant to trafficking

Sci Rep. 2017 Jun 29;7(1):4379. doi: 10.1038/s41598-017-04728-z.

Abstract

Dendritic release of dopamine activates dopamine D2 autoreceptors, which are inhibitory G protein-coupled receptors (GPCRs), to decrease the excitability of dopamine neurons. This study used tagged D2 receptors to identify the localization and distribution of these receptors in living midbrain dopamine neurons. GFP-tagged D2 receptors were found to be unevenly clustered on the soma and dendrites of dopamine neurons within the substantia nigra pars compacta (SNc). Physiological signaling and desensitization of the tagged receptors were not different from wild type receptors. Unexpectedly, upon desensitization the tagged D2 receptors were not internalized. When tagged D2 receptors were expressed in locus coeruleus neurons, a desensitizing protocol induced significant internalization. Likewise, when tagged µ-opioid receptors were expressed in dopamine neurons they too were internalized. The distribution and lack of agonist-induced internalization of D2 receptors on dopamine neurons indicate a purposefully regulated localization of these receptors.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Action Potentials
  • Animals
  • Autoreceptors / genetics
  • Autoreceptors / metabolism*
  • Dopamine
  • Dopaminergic Neurons / metabolism
  • Endocytosis
  • Female
  • Gene Expression
  • Gene Knock-In Techniques
  • Genes, Reporter
  • Male
  • Mice
  • Mice, Transgenic
  • Protein Transport
  • Receptors, Dopamine D2 / genetics
  • Receptors, Dopamine D2 / metabolism*
  • Recombinant Fusion Proteins
  • Signal Transduction

Substances

  • Autoreceptors
  • Receptors, Dopamine D2
  • Recombinant Fusion Proteins
  • Dopamine