The Role of AMPAR Trafficking Mediated by Neuronal Pentraxins in Cocaine-induced Neuroadaptations.

Glutamate AMPA receptors (AMPAR) in the nucleus accumbens have an important role in cocaine-induced neuroadaptations. Neuronal pentraxins function in the extracellular matrix to bind AMPAR. Three neuronal pentraxins have been described Narp, NP1 and NPR. Narp and NP1 cluster AMPA receptors, while NPR contributes to removing AMPA receptors during mGluR-dependent long-term depression. We recently demonstrated that each pentraxin contributes to cocaine-induced neuroadaptations in a way that is consistent with its role in AMPAR clustering and trafficking. Thus, Narp and NP1 deletion promoted cocaine-induced place preference and showed blunted AMPA induced locomotion after cocaine withdrawal. In contrast NPR deletion augmented the AMPA response and was without effect on place preference. Consistent with reduced AMPA responsiveness after chronic cocaine in Narp KO mice, GluR1 was reduced in the postsynaptic density (PSD) fraction of Narp KO mice withdrawn from cocaine. These findings will be discussed in light of recent data showing that rats withdrawn from cocaine have marked deficits in developing long-term potentiation and long-term depression.