UPTAKE OF 75-SELENIUM INTO THE CENTRAL-NERVOUS-SYSTEM OF THE RAT

These experiments have investigated selenium movement between blood an d the CNS in anaesthetized rats. Each animal was anaesthetized and the left femoral blood vessels cannulated for blood withdrawal and solute infusion. Each rat received 75-Se as sodium selenite infused in norma l saline and experiments lasted between 5 minutes and 5 hours during w hich blood samples were periodically taken. At termination, the CNS wa s removed, dissected and analysed with the plasma samples for 75-Se ra dioactivity by gamma-counting. Data were analyzed by multiple-time upt ake analysis. Results showed unidirectional uptake of 75-Se into the C NS and some regional differences were found. On average the CNS influx rate constant (K-in) was about 7 +/- 1 X 10(-5) ml/min/g. This indica tes that the 75-Se most likely entered the CNS in a protein-bound form .