ISSN:
1432-2072
Keywords:
Key words Excitatory amino acids
;
Drug discrimination
;
Morphine
;
Ketamine
;
NBQX
;
GYKI 52466
;
Dizocilpine
;
Substance abuse
Source:
Springer Online Journal Archives 1860-2000
Topics:
Medicine
Notes:
Abstract The effects of the AMPA-receptor antagonists NBQX and GYKI 52466 were compared with those of the NMDA-receptor channel blocker dizocilpine in two drug discrimination tests. In the first, rats were trained to discriminate morphine (2 mg/kg) from saline and in the second, to discriminate ketamine (7 mg/kg) from saline, using a two-lever food reinforced method. NBQX (1–6 mg/kg) did not substitute for either morphine or ketamine, even at a dose which reduced response rates (6 mg/kg). Likewise, the non-competitive antagonist GYKI 52466 (5 and 10 mg/kg) produced only saline lever responding in the ketamine trained rats. When tested in combination with the training drug, NBQX (4.5 mg/kg) did not alter the morphine generalisation gradient, and similarly, neither NBQX (3 mg/kg) nor GYKI 52466 (5 and 10 mg/kg) interacted with the ketamine cue. In contrast, dizocilpine (0.05 mg/kg) significantly disrupted discrimination of morphine and produced clear drug lever responding (0.0125–0.1 mg/kg) in ketamine trained rats. These results suggest that AMPA-receptor antagonists and non-competitive NMDA-antagonists have different stimulus properties.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/s002130050140
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