MANGANESE CONCENTRATION IN RAT-BRAIN - MANGANESE TRANSPORT FROM THE PERIPHERAL-TISSUES

Mn-54 distribution in the brain and peripheral tissues was studied wit h the course of time after intravenous injection of (MnCl2)-Mn-54 to s ee manganese (Mn) transport from the peripheral tissues, i.e. the live r, to the brain. One hour after injection, Mn-54 concentrations in the brain were 0.15-0.25% dose/g, and Mn-54 was largely concentrated in t he choroid plexus. One day after injection, Mn-54 in the choroid plexu s decreased remarkably. Mn-54 in other brain regions increased gradual ly after then, and reached 0.30-0.40% dose/g 6 days after injection. T his increase of Mn-54 was due to the redistribution from the periphera l tissues such as liver and pancreas, in which Mn-54 was maintained at high levels (2.0-4.0% dose/g). The increment of Mn-54 1 h to 6 days a fter injection was the largest in the hippocampus, but not in the stri atum. These results suggest that the delivery of Mn from the liver to the brain is not involved in preferential Mn accumulation in the basal nuclei under physiological condition. This delivery may be important for brain function. (C) 1998 Elsevier Science Ireland Ltd.