A glutathione conjugate of hepoxilin A3: Formation and action in the rat central nervous system

Journal Article · Sun Apr 01 00:00:00 EST 1990 · Proceedings of the National Academy of Sciences of the United States of America; (USA)

DOI:https://doi.org/10.1073/pnas.87.8.3037· OSTI ID:6940457

Pace-Asciak, C R; Laneuville, O; Su, W G; Corey, E J; Gurevich, N; Wu, P; Carlen, P L ^[1]

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1. Hospital for Sick Children, Toronto, Ontario (Canada)

Incubation of (8R)- and (8S)-(1-14C)hepoxilin A3 (where hepoxilin A3 is 8-hydroxy-11,12-epoxyeicosa-(5Z,9E,14Z)-trienoic acid) and glutathione with homogenates of rat brain hippocampus resulted in a product that was identified as the (8R) and (8S) diastereomers of 11-glutathionyl hepoxilin A3 by reversed-phase high performance liquid chromatographic comparison with the authentic standard made by total synthesis. Identity was further confirmed by cleavage of the isolated product with gamma-glutamyltranspeptidase to yield the corresponding cysteinylglycinyl conjugate that was identical by reversed-phase high performance liquid chromatographic analysis with the enzymic cleavage product derived from the synthetic glutathionyl conjugate. The glutathionyl and cysteinylglycinyl conjugate are referred to as hepoxilin A3-C and hepoxilin A3-D, respectively, by analogy with the established leukotriene nomenclature. Formation of hepoxilin A3-C was greatly enhanced with a concomitant decrease in formation of the epoxide hydrolase product, trioxilin A3, when the epoxide hydrolase inhibitor trichloropropene oxide was added to the incubation mixture demonstrating the presence of a dual metabolic pathway in this tissue involving hepoxilin epoxide hydrolase and glutathione S-transferase processes. Hepoxilin A3-C was tested using intracellular electrophysiological techniques on hippocampal CA1 neurons and found to be active at concentrations as low as 16 nM in causing membrane hyperpolarization, enhanced amplitude and duration of the post-spike train afterhyperpolarization, a marked increase in the inhibitory postsynaptic potential, and a decrease in the spike threshold. These findings suggest that these products in the hepoxilin pathway of arachidonic acid metabolism formed by the rat brain may function as neuromodulators.

• OSTI ID: 6940457
• Journal Information: Proceedings of the National Academy of Sciences of the United States of America; (USA), Vol. 87:8; ISSN 0027-8424
• Country of Publication: United States
• Language: English

Related Subjects

59 BASIC BIOLOGICAL SCIENCES
ARACHIDONIC ACID
METABOLISM
GLUTATHIONE
BIOSYNTHESIS
BIOELECTRICITY
BIOLOGICAL PATHWAYS
CARBON 14 COMPOUNDS
EICOSANOIC ACID
ENZYME INHIBITORS
HIPPOCAMPUS
LIQUID COLUMN CHROMATOGRAPHY
PEPTIDE HYDROLASES
RATS
REAGENTS
TRACER TECHNIQUES
ANIMALS
BODY
BRAIN
CARBOXYLIC ACIDS
CENTRAL NERVOUS SYSTEM
CHROMATOGRAPHY
DRUGS
ELECTRICITY
ENZYMES
HYDROLASES
ISOTOPE APPLICATIONS
LABELLED COMPOUNDS
MAMMALS
MONOCARBOXYLIC ACIDS
NERVOUS SYSTEM
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANS
PEPTIDES
POLYPEPTIDES
PROTEINS
RADIOPROTECTIVE SUBSTANCES
RODENTS
SEPARATION PROCESSES
SYNTHESIS
VERTEBRATES
550201* - Biochemistry- Tracer Techniques