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Ming Li

Rat

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Olanzapine And Risperidone Disrupt Conditioned Avoidance Responding In Phencyclidine-Pretreated Or Amphetamine-Pretreated Rats By Selectively Weakening Motivational Salience Of Conditioned Stimulus, Ming Li, Wei He, Alexa Mead May 2012

Olanzapine And Risperidone Disrupt Conditioned Avoidance Responding In Phencyclidine-Pretreated Or Amphetamine-Pretreated Rats By Selectively Weakening Motivational Salience Of Conditioned Stimulus, Ming Li, Wei He, Alexa Mead

Ming Li

The rat conditioned avoidance response model is a well-established preclinical behavioral model predictive of antipsychotic efficacy. All clinically approved antipsychotic drugs disrupt conditioned avoidance responding – a feature that distinguishes them from other psychotherapeutics. We previously showed that the typical antipsychotic drug haloperidol disrupts avoidance responding by progressively attenuating the motivational salience of the conditioned stimulus (CS) in normal rats. In this study, using two pharmacological rat models of schizophrenia [e.g. phencyclidine (PCP) or amphetamine sensitization], we examined whether atypicals such as olanzapine or risperidone disrupt avoidance responding through the same behavioral mechanism. Rats were first pretreated with PCP, amphetamine, …


Amphetamine Selectively Enhances Avoidance Responding To A Less Salient Stimulus In Rats, Ming Li, Wei He, Rebecca Munro May 2012

Amphetamine Selectively Enhances Avoidance Responding To A Less Salient Stimulus In Rats, Ming Li, Wei He, Rebecca Munro

Ming Li

This preclinical study examined the psychological processes affected by amphetamine that contribute to human psychosis. Using a novel avoidance conditioning paradigm involving two conditioned stimuli (CS) with varied salience, we found that acute amphetamine (1.5 mg/ kg, i.p.) selectively enhanced avoidance responding to a less salient stimulus, but not to a salient one. These findings suggest that elevated dopaminergic activity selectively enhances the attributions of motivational salience to a less salient stimulus, a process that may bear relevance to the development of human delusional thoughts.


An Investigation Of The Behavioral Mechanisms Of Antipsychotic Action Using A Drug-Drug Conditioning Paradigm, Ming Li, Wei He, Alexa Mead May 2012

An Investigation Of The Behavioral Mechanisms Of Antipsychotic Action Using A Drug-Drug Conditioning Paradigm, Ming Li, Wei He, Alexa Mead

Ming Li

Antipsychotic drugs at noncataleptic doses selectively suppress conditioned avoidance response in rats. In our previous study, we had used a two-way active avoidance response paradigm to show that the antipsychotic-induced interoceptive state is one of the mechanisms underlying the avoidance-disruptive effect of antipsychotics. In this study, we sought to further examine this mechanism using a novel drug-drug conditioning procedure. We made use of the fact that both the typical neuroleptic haloperidol and the atypical neuroleptic olanzapine disrupt conditioned avoidance responding, whereas chlordiazepoxide (an anxiolytic) does not. We reasoned that if the antipsychotic interoceptive state is important in causing a disruption …