Blood-brain barrier choline transport in the senescent rat

Choline is an important membrane phospholipid constituent and a neurotransm itter precursor that is minimally synthesized in brain. The long-term maint enance of brain choline concentration is dependent on uptake from plasma, w hich occurs via saturable transporter at the blood-brain barrier. Previous studies have suggested that brain choline uptake declined with age. To reev aluate this, brain choline uptake in 3, 12, 24, and 28-month-old Fischer-34 4 rats was evaluated using the in situ brain perfusion technique. Minimal d ifferences were found with uptake parameters differing by similar to 10% be tween aged and adult rats for tracer levels while similar trends were obser ved at higher choline concentrations. Further, estimated V-max and K-m valu es differed by <30% between the groups. The results suggest that blood-brai n barrier choline uptake changes minimally with aging in the rat. (C) 1999 Elsevier Science Ireland Ltd. All rights reserved.