Blood-brain barrier choline transport in the senescent rat.
Choline is an important membrane phospholipid constituent and a neurotransmitter precursor that is minimally synthesized in brain. The long-term maintenance of brain choline concentration is dependent on uptake from plasma, which occurs via saturable transporter at the blood-brain barrier. Previous studies have suggested that brain choline uptake declined with age. To reevaluate this, brain choline uptake in 3, 12, 24, and 28-month-old Fischer-344 rats was evaluated using the in situ brain perfusion technique. Minimal differences were found with uptake parameters differing by approximately 10% between aged and adult rats for tracer levels while similar trends were observed at higher choline concentrations. Further, estimated Vmax and Km values differed by <30% between the groups. The results suggest that blood-brain barrier choline uptake changes minimally with aging in the rat.
Allen
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DD
Department of Pharmaceutical Sciences, School of Pharmacy, Texas Tech University HSC, Amarillo 79106-1712, USA. dallen@cortex.ama.ttuhsc.edu
Smith
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QR
D000375:Aging / Q000378:metabolism*; D000818:Animals; D001692:Biological Transport / Q000187:drug effects / Q000502:physiology; D001812:Blood-Brain Barrier / Q000187:drug effects / Q000502:physiology*; D002794:Choline / Q000493:pharmacokinetics*; D006426:Hemicholinium 3 / Q000494:pharmacology; D014179:Neurotransmitter Uptake Inhibitors / Q000494:pharmacology; D009994:Osmolar Concentration; D051381:Rats; D011916:Rats, Inbred F344
D014179:Neurotransmitter Uptake Inhibitors; D006426:Hemicholinium 3; D002794:Choline