Antipsychotic-induced Adaptations in the Somatodendritic and Synaptic Physiology

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Antipsychotics that antagonize G-protein coupled, dopaminergic receptors alleviate the symptoms of schizophrenia. Prolonged treatment with antipsychotics 'remodels' circuits of the prefrontal cortex and striatum, ameliorating the symptoms of the disease. Our central hypothesis is that this remodeling depends upon the ability of antipsychotics to trigger cell-type specific adaptations in the synaptic connectivity, dendritic architecture and intrinsic excitability of striatal and cortical neurons. Dysregulation of these key sub-cellular regions is likely to be a central factor in schizophrenia and provides an obvious linkage to glutamatergic determinants in the disease. Yet, little is known about how antipsychotics and antipsychotic-sensitive receptors influence dendritic electrogenesis, synaptic integration and plasticity in functionally relevant subpopulations of striatal and PFC neurons. The central goal of the project is to help fill this gap in our understanding, but, there are obstacles to success. One is that the neurons within both the striatum and PFC are heterogeneous. Another major obstacle is the inaccessibility of dendritic regions to physiological study. This proposal takes advantage of BAC transgenic mice, the development of two photon laser scanning microscopy and two photon laser uncaging to overcome these obstacles. These approaches will be used in conjunction with electrophysiological, pharmacological and molecular strategies that complement the other Projects in this Conte Center to pursue three Specific Aims: 1) To characterize the impact of antipsychotic treatment on somatodendritic excitability and morphology of the two principal cell types in the striatum: striatonigral and striatopallidal medium spiny neurons (MSNs); 2) To characterize the impact of antipsychotic treatment on the properties of synapses formed by the two principal inputs to striatal MSNs from the cerebral cortex and thalamus; 3) To characterize the impact of antipsychotic treatment on the somatodendritic morphology and excitability of identified subsets of prelimbic/infralimbic (PL/IL) cortex pyramidal neurons.