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Effects of Transient Forebrain Ischemia and Pargyline on Extracellular Concentrations of Dopamine, Serotonin, and Their Metabolites in the Rat Striatum as Determined by In Vivo Microdialysis
Author(s) -
Damsma G.,
Boisvert D. P.,
Mudrick L. A.,
Wenkstern D.,
Fibiger H. C.
Publication year - 1990
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.1471-4159.1990.tb02322.x
Subject(s) - microdialysis , pargyline , striatum , dopamine , serotonin , neurochemical , in vivo , pharmacology , chemistry , extracellular , medial forebrain bundle , forebrain , medicine , endocrinology , neuroscience , biology , central nervous system , biochemistry , receptor , microbiology and biotechnology
Striatal microdialysis was performed in rats subjected to 20 min of transient forebrain ischemia produced by occlusion of the carotid arteries during hemorrhagic hypotension. Extracellular changes of dopamine, serotonin, and their metabolites were monitored before, during, and after the ischemic insult at 10‐min intervals by on‐line HPLC analysis. During ischemia, extracellular dopamine increased dramatically (156 times baseline), as did 3‐methoxytyramine (3‐MT), whereas 3,4‐dihydroxyphenylacetic acid (DOPAC) and homovanillic acid (HVA) decreased (15–25% of baseline). Upon reperfusion, dopamine was cleared from the extracellular fluid within 40 min and reached a stable level (70% of baseline). DOPAC and HVA increased (250–330%) transiently and reached their maximum 1 h following reperfusion, whereas 3‐MT decreased to undetectable levels within 20 min. Although baseline levels of serotonin were not detectable, serotonin and 5‐hydroxyindoleacetic acid showed a qualitatively similar temporal pattern to dopamine and its acid metabolites. Killing rats by cervical dislocation produced changes in extracellular dopamine, serotonin, and their metabolites that were almost identical to those seen during ischemia. Pargyline pretreatment 2 h before ischemia had marginal effects on the postischemic clearing of dopamine. The pargyline pretreatment, however, did increase the survival rate of rats subjected to ischemia, and this protective effect might be due to the pargyline‐induced blockade of the postischemic monoamine oxidase‐mediated increase in dopamine metabolism and the concurrent production of the potentially neurotoxic molecule, hydrogen peroxide.