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In Vivo Microdialysis Study of the Extracellular 3,4‐Dihydroxyphenylacetic Acid in the Rat Locus Ceruleus: Topographical and Pharmacological Aspects
Author(s) -
Ortemann Catherine,
Robert Frédéric,
Renaud Bernard,
LambasSenas Laura
Publication year - 1993
Publication title -
journal of neurochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.75
H-Index - 229
eISSN - 1471-4159
pISSN - 0022-3042
DOI - 10.1111/j.1471-4159.1993.tb02163.x
Subject(s) - microdialysis , locus ceruleus , chemistry , pargyline , extracellular , in vivo , monoamine oxidase , locus coeruleus , catecholamine , medicine , pharmacology , endocrinology , biochemistry , central nervous system , dopamine , enzyme , biology , microbiology and biotechnology , dopaminergic , substantia nigra
In vivo microdialysis coupled with HPLC and electrochemical detection was used to monitor extracellular levels of 3, 4‐dihydroxyphenylacetic acid (DOPAC) of the locus ceruleus (LC) in halothane‐anesthetized rats. The identity of DOPAC was confirmed by experiments showing that the chromatographic peak was totally suppressed after inhibition of monoamine oxidase by pargyline. Histological examinations allowed to relate the quantity of DOPAC measured in the dialysates with the localization of the probe implantation site. We found that the DOPAC concentration was inversely proportional to the distance between the probe and the lateral border of the LC. Regardless of the caudorostral level of the nucleus, concentrations were maximal when the axis of the probe was 100 μ M from the lateral border of the LC and decreased by 53% when this distance reached 300 μ M . Activation of LC noradrenergic neurons by systemic administration of the α 2 ‐antagonist piperoxane increased by 100% DOPAC concentrations in LC dialysates. These results suggest that the DOPAC measured by microdialysis could be considered an indicator of the functional state of LC noradrenergic neurons.