Endogenous homovanillic acid levels differ between rat and rabbit caudate, hippocampus, and cortical regions.
Endogenous dopamine (DA) levels and its metabolites 3,4-dihydroxyphenylacetic acid (DOPAC), 3-methoxytyramine (3MT) and homovanillic acid (HVA) were measured by high-performance liquid chromatography in the entorhinal-piriform (EnPi), cingulate (CIN), sensorimotor (SSM) and visual (VIS) cortices as well as is the caudate (CAU) and hippocampus (HIP) of Sprague-Dawley (SD) rats and New Zealand (NZ) rabbits. The DA, DOPAC and 3MT contents were similar in both species. The HVA levels however, although they followed DA distribution, were several-fold higher in NZ rabbits than in SD rats for all cortices, HIP and CAU. In addition, total metabolite contents and DA turnover (estimated from 'DA metabolite/DA' ratios) were significantly higher in NZ rabbits than in SD rats, suggesting an increased release and/or metabolism in the former species. The HVA/DA ratios were much higher for NZ rabbit regions than for SD rats, indicating an increased DA release in the former species since the DOPAC/DA ratios (index of intraneuronal degradation) were similar.
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Département de physiologie, Faculté de Médecine, Université de Montréal, Québec, Canada.
Dewar
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D000818:Animals; D002421:Caudate Nucleus / Q000378:metabolism*; D002540:Cerebral Cortex / Q000378:metabolism*; D006624:Hippocampus / Q000378:metabolism*; D006719:Homovanillic Acid / Q000378:metabolism*; D008297:Male; D011817:Rabbits; D051381:Rats; D011919:Rats, Inbred Strains
D006719:Homovanillic Acid