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Faculty
Deborah L. Armstrong, Ph.D. Research Interests My major research interests as present focus on hippocampal pyramidal and granule cell synaptic plasticity utilizing electro physiological and neurochemical techniques. We are using intracellular recording methods to assess the effects of low closes of industrial toxins and endogenous brain peptides on long-term potentiation (LTP) in rat brain tissue slices. LTP is an activity dependent change in synaptic efficacy that is associated with voltage and ligand gated calcium channels. My long-term goal is to develop the hippocampal slice as a screening device to detect early functional changes in synapses that are associated with neuronal toxicity. We have already been successful in identifying subtle changes in pyramidal cell responses that are induced by in vitro application of organotin compounds, such as trimethyltin. These changes in passive and active membrane properties are specific to trimethyltin, a chemical used in the plastics industry that is known to produce lesions in the central nervous system. The observed decreases in input resistance are calcium-dependent and we are continuing our efforts to characterize this effect. Recent Publications Wayner MJ, Armstrong DL, Phelix CF, Oomura Y. Orexin-A (Hypocretin-1) and leptin enhance LTP in the dentate gyrus of rats in vivo. Peptides. 2004 Jun;25(6):991-6. Wayner MJ, Armstrong DL, Phelix CF. Ethanol effects on dentate granule cell LTP. Neurotox Res. 2004;5(8):599-604. Wayner MJ, Armstrong DL, Phelix CF, Wright JW, Harding JW. Angiotensin IV enhances LTP in rat dentate gyrus in vivo. Peptides. 2001 Sep;22(9):1403-14. Kramar EA, Armstrong DL, Ikeda S, Wayner MJ, Harding JW, Wright JW. The effects of angiotensin IV analogs on long-term potentiation within the CA1 region of the hippocampus in vitro. Brain Res. 2001 Apr 6;897(1-2):114-21. Wayner MJ, Tracy HA, Armstrong DL, Phelix CF. Air righting: role of the NMDA receptor channel and hippocampal LTP. Physiol Behav. 2000 Jun 1-15;69(4-5):505-10.
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