Stress, Chemical Defense Agents and Cholinergic Receptors
Final rept. 1 Nov 1987-30 Jun 1991
TEXAS COLL OF OSTEOPATHIC MEDICINE FORTWORTH DEPT OF PHARMACOLOGY
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The goal of this project is to assess the effects of exposure to a chemical defense agent XGD soman on anxiety and stress, by using rat models of anxiety conditioned emotional response, CER and unconditioned non-specific stress. To test for changes in anxiety, extinction from CER was measured, based on the hypothesis that increased anxiety produced by environmental exposures would prolong extinction. The specific experiments determined the plasticity of muscarinic cholinergic binding-sites in the central nervous system. The effects of acute exposure to doses of soman on lethality and well-characterized behaviors were examined, and found to be consistent with previous reports. The binding of radiolabelled cholinergic ACh ligands to brain tissue was studied in vitro. The major findings are that CER produces increases in acetycholine turnover in brain areas involved in anxiety, and that primarily post-synaptic M1 ACh receptors decrease. These neurochemical phenomena are directly correlated with several behaviors, including acquisition and extinction of CER and non- specific stress. If soman exposure increased anxiety under any conditions, this should be reflected in increased time of CER extinction and changes in receptors the behavioral response was not observed, so receptor function was not assessed. Therefore, the effect of soman exposure on anxiety is not likely to be specific to the cholinergic system. Anxiety, Acetylcholine, CD Agents, Acetylcholinesterase, Inhibitors, Brain receptors, RA1.
- Anatomy and Physiology
- Chemical, Biological and Radiological Warfare