Rapid postmortem increase in extracellular dopamine in the rat brain as assessed by brain microdialysis.
Extracellular dopamine (DA) and its metabolites 3,4-dihydroxyphenylacetic acid (DOPAC) and homovanillic acid (HVA) in rat nucleus accumbens were determined before and shortly following death using microdialysis. A maximal 400-fold increase in the output of DA was observed within the first 5 min of death. DA output remained elevated over the following hour at a level of approximately 70-fold above pre-death values. In contrast to that of DA, DOPAC and HVA output gradually declined. Before death the extracellular DOPAC/DA ratio was about 250; after death this ratio dropped to 0.44 at 5 min. These observations may have important implications for experiments measuring the output of (endogenous) DA and its metabolites from brain tissue in vitro: autoregulation of, e.g., transmitter release and synthesis in vitro may be seriously disrupted by the observed depletion of transmitter storage granules.
Vulto
A G
AG
Department of Pharmacology, Karolinska Institute, Stockholm, Sweden.
Sharp
T
T
Ungerstedt
U
U
Versteeg
D H
DH
D015102:3,4-Dihydroxyphenylacetic Acid / Q000378:metabolism; D000818:Animals; D001921:Brain / Q000378:metabolism*; D002851:Chromatography, High Pressure Liquid; D003956:Dialysis / Q000379:methods; D004298:Dopamine / Q000378:metabolism*; D004563:Electrochemistry / Q000379:methods; D005110:Extracellular Space / Q000378:metabolism*; D006719:Homovanillic Acid / Q000378:metabolism; D008297:Male; D009994:Osmolar Concentration; D011180:Postmortem Changes; D051381:Rats; D011919:Rats, Inbred Strains; D013997:Time Factors
D015102:3,4-Dihydroxyphenylacetic Acid; D004298:Dopamine; D006719:Homovanillic Acid