EFFECT OF LITHIUM CHLORIDE ADMINISTRATION ON BRAIN AND HEART NOREPINEPHRINE TURNOVER RATES

The effect of Li+ on NE turnover rates in rat heart and brain was studied. Turnover rates were determined in brain and heart by blocking tyrosine hydroxylase with L-α-methyltyrosine and following the decline of NE with time or in heart by injecting3H-NE and following the decline of NE specific activity with time. Subacute treatment with LiCl in doses that maintained a serum lithium level within the clinically therapeutic range caused: 1. A 95% increase in brain NE turnover rate without altering the steady-state level of the amine. 2. A slight but not significant increase in heart NE turnover. 3. The selective increase in brain NE turnover, compared to heart, may be attributed to the higher tissue levels of Li+ found in the brain under the conditions of study. © 1969 Springer-Verlag.