The influence of histamine on metabolism of dopamine and serotonin in the rat striatum.

The influence of histamine on metabolism of dopamine and serotonin in the rat striatum. Acta Physiol. Pol., 1977, 28 (2): 101--105. Histamine-2HC1 (Hi) given in a dose of 500 micron g did not change DA level in the striatum but HVA was increased by approx. 50%. The Hi-induced rise of HVA level was prevented in animals pretreated with an antihistaminic drug--mepyramine. The pretreatment of rats with atropine reduced significantly the Hi-induced rise of HVA concentration. Hi did not significantly influence 5-HT content in the striatum while the level of 5-HIAA was simultaneously increased by 15%. It is concluded that Hi-induced elevation of HVA content is not a direct effect of Hi on dopaminergic neurons but the Hi action is exerted indirectly through cholinergic system. The increase of serotoninergic activity is probably a consequence of an increased activity of dopaminergic neurons in the striatum.