Behavioural pharmacology
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Behavioural pharmacology · Mar 1996
Tolerance to the discriminative stimulus and reinforcing effects of ketamine.
In order to examine whether tolerance develops to the discriminative stimulus and reinforcing effects of ketamine, rats were trained either to discriminate ketamine (10mg/kg) from saline or to self-administer ketamine (1.1mg/kg/injection), and then treated with chronic ketamine (32mg/kg), administered i.p. every 8 hours for 7 days. No shift in the dose-response curve for either paradigm was obtained following this chronic regimen. ⋯ These results suggest that tolerance to the discriminative stimulus and reinforcing effects of ketamine develops during training. Examination of the self-administration training data support this assumption, since inter-reinforcer time decreases, reflecting an increase in ketamine intake over training sessions.