Regional blood-brain lactate influx.
Regional blood-to-brain lactate transport was studied in chloral hydrate anesthetized rats using the single pass, dual-label, indicator fractionation, right atrial injection method. Lactate influx was resolved into two components, a saturable, stereospecific (to the L-enantiomer) component and a non-saturable, non-stereospecific diffusional component. The saturable component was found to have a low efficiency and moderate capacity with transport affinity coefficients between 6 and 14 mM and transport maxima of 23-40 mumol/100 g/min in the various brain regions. Lactate transport was not inhibited by probenecid. The diffusional component was determined from D-lactate influx measurements and the regional linear diffusion coefficients ranged from 0.020 to 0.036 ml/g/min. At the usual levels of plasma lactate (1-1.5 mM) these two influx components were about equal. The relative contribution of the non-stereospecific diffusional component was increased at higher plasma lactate concentrations. Lactate clearance, estimated by the total apparent permeability x surface area products was between 6 and 8 ml/100 g/min.
LaManna
J C
JC
Department of Neurology, University Hospitals of Cleveland, OH.
Harrington
J F
JF
Vendel
L M
LM
Abi-Saleh
K
K
Lust
W D
WD
Harik
S I
SI
D000818:Animals; D001812:Blood-Brain Barrier / Q000187:drug effects; D001923:Brain Chemistry / Q000187:drug effects / Q000502:physiology*; D002560:Cerebrovascular Circulation; D005947:Glucose / Q000378:metabolism; D007444:Inulin; D007773:Lactates / Q000097:blood / Q000378:metabolism*; D008297:Male; D011339:Probenecid / Q000494:pharmacology; D011773:Pyruvates / Q000097:blood; D019289:Pyruvic Acid; D051381:Rats; D017208:Rats, Wistar; D013237:Stereoisomerism
D007773:Lactates; D011773:Pyruvates; D019289:Pyruvic Acid; D007444:Inulin; D005947:Glucose; D011339:Probenecid