Abstract
Local perfusion of pGlu-Glu-Pro-NH2, an endogenous peptide structurally related to thyrotropine-releasing hormone (TRH), via in vivo microdialysis into the rat hippocampus did not change the basal level of extracellular acetylcholine. However, co-perfusion of pGlu-Glu-Pro-NH2 with TRH in equimolar concentrations yielded a significant attenuation of TRH-induced acetylcholine release. The results have supported the study's hypothesis that pGlu-Glu-Pro-NH2 opposes the cholinergic effect of TRH in the mammalian central nervous system. The enantiomer pGlu-d-Glu-Pro-NH2 affected neither basal extracellular nor TRH-induced increase of acetylcholine levels.
Publication types
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Research Support, N.I.H., Extramural
MeSH terms
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Acetylcholine / metabolism
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Animals
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Brain Chemistry / drug effects
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Brain Chemistry / physiology*
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Drug Synergism
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Extracellular Fluid / drug effects
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Extracellular Fluid / metabolism
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Hippocampus / drug effects
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Hippocampus / metabolism*
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Male
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Microdialysis
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Molecular Structure
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Neurotransmitter Agents / metabolism
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Neurotransmitter Agents / pharmacology
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Presynaptic Terminals / drug effects
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Presynaptic Terminals / metabolism
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Pyrrolidonecarboxylic Acid / analogs & derivatives*
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Pyrrolidonecarboxylic Acid / metabolism
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Pyrrolidonecarboxylic Acid / pharmacology
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Rats
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Rats, Sprague-Dawley
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Synaptic Transmission / drug effects
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Synaptic Transmission / physiology
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Thyrotropin-Releasing Hormone / analogs & derivatives*
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Thyrotropin-Releasing Hormone / metabolism*
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Thyrotropin-Releasing Hormone / pharmacology
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Up-Regulation / drug effects
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Up-Regulation / physiology
Substances
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Neurotransmitter Agents
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Thyrotropin-Releasing Hormone
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pyroglutamyl-glutamyl-proline amide
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Acetylcholine
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Pyrrolidonecarboxylic Acid