NMU psychology professor Adam Prus received a grant for this research from the National Institutes of Mental Health. The abstracts of the presentations the students gave at the Society for Neuroscience meeting can be found below:
The effects of the neurotensin receptor-1 agonist PD149163 on signal detection performance in rats
Todd M. Hillhouse, Ashley Schmeling, and Adam J. Prus, Northern Michigan University, Department of Psychology
ABSTRACT: Neurotensin is a neuropeptide neurotransmitter that has cognitively relevant interactions with multiple neurotransmitter systems. Brain penetrant agonists of neurotensin NT1 receptors have exhibited atypical antipsychotic drug-like effects in animals models, including reversal of psychotomimetic-induced sensory gating deficits, but have yet to be thoroughly evaluated in animal cognitive models. The present study sought to evaluate the effects of the NT1 receptor agonist PD149163 on attention using a visual signal detection operant task in rats. PD149163 did not significantly alter the percentage of signals detected (hits) nor alter the percentage of non-signals correctly identified (correct rejections). Both the atypical antipsychotic drug clozapine and the dopamine D2/3 receptor antagonist and typical antipsychotic drug raclopride significantly decreased percent hits. Nicotine, used as a positive control, significantly increased both percent hits and percent correct rejections. Based upon these and previous findings, PD149163 is a putative atypical antipsychotic drug that appears neither beneficial nor detrimental for attention.
Effects of atypical antipsychotic drugs on differential reinforcement of low rate 72s performance in rats
Zachary Shankland, Lawrence Carey, Ashley Schmeling and Adam J. Prus
ABSTRACT: While generally not considered treatments for depression, some atypical antipsychotic drugs (e.g., quetiapine) produce improvements in mood and related negative symptoms in schizophrenia. Moreover, atypical antipsychotic drugs may augment antidepressant drug effects in treatment resistant depression. The present study sought to evaluate newer and experimental atypical antipsychotic drugs in rats using a differential reinforcement of low rate 72s (DRL-72s) task, a standard antidepressant screening model. An antidepressant effect is characterized by a significant increase in reinforcement rate and in the ratio of reinforcers / responses. Neither the atypical antipsychotic drug quetiapine nor the quetiapine active metabolite and monoamine reuptake inhibitor N-Desalkylquetiapine, exhibited antidepressant effects in this task. However, the atypical antipsychotic drug risperidone significantly increase both reinforcement rates and the ratio of reinforcers / responses. The neurotensin NT1 receptor agonist and putative atypical antipsychotic drug PD149163 exhibited an increase in reinforcement rates and reinforcer/response ratios, but these effects did not occur at the same dose. Finally, the tricyclic antidepressant drug imipramine significantly increased reinforcement rates and the reinforcer/response ratio. The present findings extend DRL-72s profile to selected atypical antipsychotic drugs and novel atypical antipsychotic drug mechanisms.
The students who presented:
Lawrence Carey – Undergraduate Psychology Major
Ashley Schmeling – Undergraduate Psychology Major
Zachary Shankland – Graduate Student
Todd Hillhouse – Graduated from NMU