The activating effect of histamine on the central nervous system.

Publisher Summary A critical analysis of the action of histamine (H) on the central nervous system must consider the route of administration (intravascular, intraventricular, or intracerebral ), the visceral, somatic behavioral, and electrographic effects of this substance on the central nervous system. The neurophysiological approach is rather recent and particularly important, since the neurohumoral nature of H becomes more and more evident. Scarcely investigated was histamine's involvement in the regulation of wakefulness and its relations to other neurohumors, such as catecholamines or serotonin. Previous experimental data suggested that H has a definite waking effect, but the mechanisms of this effect need closer analysis. This chapter reviews, on one hand, the previous investigations devoted to the action of H on the central nervous system. On the other hand, it reports the results of the experiments performed to differentiate the mechanisms of the agerent and central effects of H on the brain. It is indeed necessary to specify the extent to which the waking effect is mediated reflexly by afferent systems and the extent to which it is of a direct central nature.