Alterations in concentrations of dihydroxyphenylacetic acid in the median eminence of rats euthanatized with pentobarbital.
Concentrations of dopamine (DA) and one of its major metabolites, dihydroxyphenylacetic acid (DOPAC), were determined in selected brain regions of rats that were euthanatized either by decapitation or by intravenous injections of pentobarbital or Fatal Plus, a commercial preparation that contains pentobarbital. When compared with values in decapitated brains, pentobarbital increased the concentration of DOPAC in the median eminence, which contains terminals of tuberoinfundibular dopaminergic (TIDA) neurons. Fifteen minutes of restraint reduced the concentration of DOPAC in the median eminence of rats killed by decapitation or by injections of pentobarbital, indicating that pentobarbital does not mask restraint-induced decrease in TIDA neuronal activity. In contrast, none of the manipulations altered DA or DOPAC concentrations in the striatum, which contains terminals of nigrostriatal dopaminergic neurons. Thus, changes in the concentrations of DOPAC in the median eminence (an index of TIDA neuronal activity) induced by stress can be detected in rats euthanatized by either decapitation or an injection of pentobarbital.
Zinn
S A
SA
Department of Animal Science, Michigan State University, East Lansing 48824.
Lookingland
K J
KJ
Tucker
H A
HA
Moore
K E
KE
D015102:3,4-Dihydroxyphenylacetic Acid / Q000032:analysis*; D000758:Anesthesia / Q000662:veterinary; D000818:Animals; D004298:Dopamine / Q000032:analysis*; D005065:Euthanasia / Q000662:veterinary*; D008297:Male; D008473:Median Eminence / Q000032:analysis* / Q000378:metabolism; D010424:Pentobarbital / Q000494:pharmacology*; D010648:Phenylacetates; D051381:Rats; D012149:Restraint, Physical
D010648:Phenylacetates; D015102:3,4-Dihydroxyphenylacetic Acid; D010424:Pentobarbital; D004298:Dopamine