The Journal of Neuroscience, 2001, 21:RC133:1-6
RAPID COMMUNICATION
Previous Exposure to Amphetamine Enhances the Subsequent
Locomotor Response to a D1 Dopamine Receptor Agonist When
Glutamate Reuptake Is Inhibited
Jeong-Hoon
Kim,
Mary
Perugini,
Jennifer D.
Austin, and
Paul
Vezina
Department of Psychiatry, The University of Chicago, Chicago,
Illinois 60637
The role of nucleus accumbens (NAcc) glutamate (GLU) and
D1 dopamine (DA) receptor activation in the expression of
locomotor sensitization to amphetamine (AMPH) was investigated in rats. Rats were preexposed to either AMPH or saline, and 2 weeks later their
locomotion was assessed after a microinjection into the NAcc of the
selective glutamate reuptake blocker
L-trans-pyrrolidine-2,4-dicarboxylic acid
(PDC) (10 nmol per side), the D1-like DA receptor agonists SKF82958 (2.4 nmol per side) and SKF38393 (3.1 nmol per side), the
D2-like DA receptor agonist quinelorane (3.1 nmol per
side), or AMPH (6.8 nmol per side). All compounds other than
quinelorane increased locomotion when infused into the NAcc. Only AMPH,
however, produced enhanced locomotion in AMPH relative to
saline-preexposed rats. When additional rats were tested after NAcc
infusions of PDC together with either SKF82958 or quinelorane, enhanced
locomotion was observed in AMPH relative to saline-preexposed rats
after NAcc PDC + SKF82958. These results suggest that in the NAcc,
increased GLU neurotransmission and activation of D1 DA
receptors, neither of which is by itself sufficient, together
contribute to the expression of locomotor sensitization by AMPH. They
stress, with other findings, the importance of GLU-DA interactions in
the NAcc not only in the generation of acute stimulant drug effects but
in sensitized responding to these drugs as well.
Key words:
dopamine; D1- and D2-like
dopamine receptors; glutamate; nucleus accumbens; amphetamine; sensitization; locomotor activity; L-PDC; SKF82958; SKF38393; quinelorane
Copyright © Society for Neuroscience 0270-6474//$05.00/0