The Journal of Neuroscience, July 15, 2002, 22(14):5817-5822
BRIEF COMMUNICATION
Enhanced Inhibition of Synaptic Transmission by Dopamine in the
Nucleus Accumbens during Behavioral Sensitization to Cocaine
Corinne
Beurrier and
Robert C.
Malenka
Nancy Pritzker Laboratory, Department of Psychiatry and Behavioral
Sciences, Stanford University School of Medicine, Palo Alto, California
94304
Neural adaptations in the nucleus accumbens (NAc), a key component
of the mesolimbic dopamine (DA) system, are thought to mediate several
of the long-term behavioral sequelas of chronic in vivo
exposure to drugs of abuse. Here, we examine whether the modulation of
excitatory synaptic transmission by DA in the NAc shell is modified
after chronic cocaine exposure that induced behavioral sensitization.
The DA-induced inhibition of AMPA receptor-mediated synaptic responses
was enhanced in cocaine-treated mice, an effect that was caused by
activation of D1-like receptors. DA did not enhance NMDA
receptor-mediated synaptic responses in saline- and cocaine-treated
mice or in the dorsal striatum of control mice. We hypothesize that the
enhanced inhibitory effects of DA on synaptic transmission in the NAc
are one of a number of adaptations that contribute to a decrease in
excitatory drive to NAc after exposure to drugs of abuse.
Key words:
addiction; cocaine; dopamine; nucleus accumbens; striatum; synaptic transmission; glutamate; AMPA receptors; NMDA
receptors
Copyright © 2002 Society for Neuroscience 0270-6474/02/22145817-06$05.00/0