Schizophrenia & Mania – Conditioned Avoidance Response
In the conditioned avoidance response (CAR) test, a foot-shock is delivered after presentation of a stimulus (e.g., light and tone). Subjects are trained in the task such that delivery of the mild foot-shock is avoided, rather than escaped after the start of shock delivery. Antipsychotic medications impair the ability of the test subject to avoid food-shock, but do not affect the escape response. By contrast, a compound that induces sedation (for example, a benzodiazepine) has no effect on avoidance responses. CAR is therefore predictive of antipsychotic efficacy and is frequently used to screen potential anti-psychotic medications.
Dose response for the effects of the typical antipsychotic haloperidol on avoidance response (left) and escape failures (right) in Wistar rats. Haloperidol (0.3 and 0.6 mg/kg; i.p.) attenuates avoidance responses with no effect on escape failures.
Dose response for the effects of the atypical antipsychotic aripiprazole on avoidance response (left) and escape failures (right) in Wistar rats. Aripiprazole (3 - 30 mg/kg; i.p.) attenuates avoidance responses with no effect on escape failures.
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Dose response for the effects of the atypical antipsychotic olanzapine on avoidance response (left) and escape failures (right) in Wistar rats. Olanzapine (2 and 5 mg/kg; i.p.) attenuates avoidance responses, with an increase in escape failures at a higher dose (5 mg/kg).
Dose response for the effects of the atypical antipsychotic risperidone on avoidance response (left) and escape failures (right) in Wistar rats. Risperidone (0.3 and 1 mg/kg; i.p.) attenuates avoidance responses, with an increase in escape failures at a higher dose (1 mg/kg).
