Amine Neurotransmitter Regulation of Long-Term Synaptic Plasticity in Hippocampus.
Annual rept. 1 Apr 86-31 Mar 87,
BAYLOR COLL OF MEDICINE HOUSTON TX
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The overall goal of this research project is to investigate the mechanisms of long-term synaptic potentiation LTP in hippocampus, with particular emphasis on the modulation of LTP by amine neurotransmitters. It was shown previously that norepinephrine NE enhances the magnitude, duration, and probability of induction of LTP at mossy fiber synapses. During the second year of this grant, intracellular recording techniques were utilized to explore various cellular hypotheses associated with this NE modulation of LTP. It was shown that the injection of cyclic AMP cAMP into the postsynaptic neuron could mimic the action of NE in enhancing LTP. This very important series of experiments has led to the current working hypothesis that NE modulates LTP by increasing cAMP in the postsynaptic neuron. Additional experiments, which explored possible membrane mechanisms associated with the action of NE on LTP, indicated that NE, through beta-adrenoceptors and cAMP, increases the activity of at least one type of voltage-dependent calcium channel. Other work associated with this grant involved the development of a preparation of mossy fiber synaptosomes for electrophysiological analysis and computer models for simulation of neural networks comprised of realistically represented hippocampal neurons.
- Anatomy and Physiology