Histamine H3 receptor-mediated inhibition of serotonin release in the rat brain cortex

Summary Rat brain cortex slices preincubated with ³H-serotonin were superfused with physiological salt solution (containing citalopram, an inhibitor of serotonin uptake) and the effect of histamine on the electrically (3 Hz) evoked ³H overflow was studied. Histamine decreased the evoked overflow in a concentration-dependent manner. The inhibitory effect of histamine was antagonized by impromidine and burimamide, but was not affected by pheniramine, ranitidine, metitepine and phentolamine. Given alone, impromidine facilitated the evoked overflow, whereas burimamide, pheniramine and ranitidine had no effect. The results suggest that histamine inhibits serotonin release in the rat brain cortex via histamine H3 receptors, which may be located presynaptically.Send offprint requests to E. Schlicker at the above address