ISSN:
1471-4159
Source:
Blackwell Publishing Journal Backfiles 1879-2005
Topics:
Medicine
Notes:
Abstract: The present investigation using labeled pyruvate describes the regional distribution and kinetics of the monocarboxylic acid carrier at the blood–brain barrier of conscious rats. The experimental procedure involved the arterial injection of a single bolus of 200 μ1 containing [1-14C]pyruvate, [3H]water, and varying concentrations of unlabeled pyruvate into the common carotid via an indwelling externalized catheter. The hemisphere ipsi-lateral to the injection and rostral to the midbrain was removed and dissected into five regions. A kinetic analysis revealed no significant regional differences in Km values with an overall average of 1.37 mM. However, there was regional variation in the density of the monocarboxylic acid carrier as indicated by varied levels of the kinetic constant Vmax. The cortex showed the highest Vmax value of 0.42 ± 0.08 μmol/min/g whereas values for the caudate/putamen, thalamus/hypothalamus, and remaining portion of hemisphere ranged significantly lower at 0.22–0.27 μmol/min/g. The Vmax for the hippocampus was intermediate at 0.37 ± 0.12 μmol/min/g. The nonsaturable carrier described kinetically by KD had an overall average of 0.034 ml/min/g. The present study confirms quantitatively previous results suggesting a variable regional distribution of the monocarboxylic acid carrier.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1111/j.1471-4159.1986.tb01756.x
