TY - JOUR
T1 - Cocaine-induced potentiation of synaptic strength in dopamine neurons
T2 - Behavioral correlates in GluRA(-/-) mice
AU - Dong, Y.
AU - Saal, D.
AU - Thomas, M.
AU - Faust, R.
AU - Bonci, A.
AU - Robinson, T.
AU - Malenka, R. C.
PY - 2004/9/28
Y1 - 2004/9/28
N2 - Synaptic plasticity in the mesolimbic dopamine (DA) system is thought to contribute to the neural adaptations that mediate behavioral sensitization, a model for core aspects of addiction. Recently, it has been demonstrated that multiple classes of drugs of abuse, as well as acute stress, enhance strength at excitatory synapses on midbrain DA neurons. Here, we show that both the cocaine- and stress-induced synaptic enhancement involves an up-regulation of α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptors. This enhancement requires the α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor subunit GluRA as evidenced by its absence in mice lacking this subunit. The cocaine-elicited, but not the stress-elicited, synaptic potentiation in DA neurons was blocked by a D1-like receptor antagonist, indicating that the in vivo triggering mechanisms differ for these forms of experience-dependent synaptic modification. Surprisingly, behavioral sensitization to cocaine was elicited in GluRA(-/-) mice, indicating that potentiation of excitatory synaptic transmission in DA neurons is not necessary for this form of behavioral plasticity. However, GluRA(-/-) mice did not exhibit a conditioned locomotor response when placed in a context previously paired with cocaine, nor did they exhibit conditioned place preference in response to cocaine. We suggest that the drug-induced enhancement of excitatory synaptic transmission in midbrain DA neurons, although not required for behavioral sensitization per se, may contribute to the attribution of incentive value to drug-associated cues.
AB - Synaptic plasticity in the mesolimbic dopamine (DA) system is thought to contribute to the neural adaptations that mediate behavioral sensitization, a model for core aspects of addiction. Recently, it has been demonstrated that multiple classes of drugs of abuse, as well as acute stress, enhance strength at excitatory synapses on midbrain DA neurons. Here, we show that both the cocaine- and stress-induced synaptic enhancement involves an up-regulation of α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptors. This enhancement requires the α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor subunit GluRA as evidenced by its absence in mice lacking this subunit. The cocaine-elicited, but not the stress-elicited, synaptic potentiation in DA neurons was blocked by a D1-like receptor antagonist, indicating that the in vivo triggering mechanisms differ for these forms of experience-dependent synaptic modification. Surprisingly, behavioral sensitization to cocaine was elicited in GluRA(-/-) mice, indicating that potentiation of excitatory synaptic transmission in DA neurons is not necessary for this form of behavioral plasticity. However, GluRA(-/-) mice did not exhibit a conditioned locomotor response when placed in a context previously paired with cocaine, nor did they exhibit conditioned place preference in response to cocaine. We suggest that the drug-induced enhancement of excitatory synaptic transmission in midbrain DA neurons, although not required for behavioral sensitization per se, may contribute to the attribution of incentive value to drug-associated cues.
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U2 - 10.1073/pnas.0401553101
DO - 10.1073/pnas.0401553101
M3 - Article
C2 - 15375209
AN - SCOPUS:4644276214
SN - 0027-8424
VL - 101
SP - 14282
EP - 14287
JO - Proceedings of the National Academy of Sciences of the United States of America
JF - Proceedings of the National Academy of Sciences of the United States of America
IS - 39
ER -