Activation of D1 dopamine receptors increases surface expression of AMPA receptors and facilitates their synaptic incorporation in cultured hippocampal neurons.
Considerable evidence indicates that neuroadaptations leading to addiction involve the same cellular processes that enable learning and memory, such as long-term potentiation (LTP), and that psychostimulants influence LTP through dopamine (DA)-dependent mechanisms. In hippocampal CA1 pyramidal neurons, LTP involves insertion of alpha-amino-3-hydroxy-5-methylisoxazole-4-propionate (AMPA) receptors into excitatory synapses. We used dissociated cultures to test the hypothesis that D1 family DA receptors influence synaptic plasticity in hippocampal neurons by modulating AMPA receptor trafficking. Brief exposure (5 min) to a D1 agonist increased surface expression of glutamate receptor (GluR)1-containing AMPA receptors by increasing their rate of externalization at extrasynaptic sites. This required the secretory pathway but not protein synthesis, and was mediated mainly by protein kinase A (PKA) with a smaller contribution from Ca2+-calmodulin-dependent protein kinase II (CaMKII). Prior D1 receptor stimulation facilitated synaptic insertion of GluR1 in response to subsequent stimulation of synaptic NMDA receptors with glycine. Our results support a model for synaptic GluR1 incorporation in which PKA is required for initial insertion into the extrasynaptic membrane whereas CaMKII mediates translocation into the synapse. By increasing the size of the extrasynaptic GluR1 pool, D1 receptors may promote LTP. Psychostimulants may usurp this mechanism, leading to inappropriate plasticity that contributes to addiction-related behaviors.
Gao
Can
C
Department of Neuroscience, The Chicago Medical School at Rosalind Franklin University of Medicine and Science, North Chicago, Illinois 60064-3095, USA.
Sun
Xiu
X
Wolf
Marina E
ME
D000818:Animals; D000831:Animals, Newborn; D002478:Cells, Cultured; D015259:Dopamine Agents / Q000494:pharmacology; D004347:Drug Interactions; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005260:Female; D015870:Gene Expression / Q000187:drug effects / Q000502:physiology; D006624:Hippocampus / Q000166:cytology*; D007150:Immunohistochemistry / Q000379:methods; D008297:Male; D009474:Neurons / Q000166:cytology* / Q000187:drug effects / Q000502:physiology*; D011247:Pregnancy; D021381:Protein Transport / Q000187:drug effects; D051381:Rats; D017207:Rats, Sprague-Dawley; D018091:Receptors, AMPA / Q000378:metabolism*; D017447:Receptors, Dopamine D1 / Q000378:metabolism*; D013569:Synapses / Q000187:drug effects / Q000502:physiology*; D013997:Time Factors
D015259:Dopamine Agents; D004791:Enzyme Inhibitors; D018091:Receptors, AMPA; D017447:Receptors, Dopamine D1