Inactivation of presynaptic 5-HT autoreceptors by lithium in rat hippocampus.

The effect of lithium ion on the electrically stimulated 5-[3H]hydroxytryptamine (5-HT) release from the rat hippocampal slices preloaded with [3H]5-HT was studied. Electrically stimulated [3H]5-HT release decreased when the slices were exposed to 5-HT in a concentration-dependent manner. Lithium (2.5 mM) did not affect [3H]5-HT release when added alone to the superfusion medium. However, the inhibitory effect of 5-HT (1 microM) on [3H]5-HT release was abolished by lithium. The results suggest that lithium may inhibit the regulation of 5-HT release via presynaptic 5-HT autoreceptors in rat hippocampus.