Related Experiment Video
Updated: Feb 27, 2026

Drug-induced Sensitization of Adenylyl Cyclase: Assay Streamlining and Miniaturization for Small Molecule and siRNA Screening Applications
Published on: January 27, 2014
Desensitized D2 autoreceptors are resistant to trafficking
Brooks G Robinson1, James R Bunzow1, Jonathan B Grimm2
1The Vollum Institute, Oregon Health and Science University, 3181S.W. Sam Jackson Pk. Rd., Portland, OR, 97239, USA.
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.
Related Concept Videos
Desensitization and Tachyphylaxis
GPCR Desensitization
Drugs Affecting Neurotransmitter Synthesis
Drugs Affecting Neurotransmitter Release or Uptake
Spare Receptors
Neurochemical Transmission: Sites of Drug Action

