Histamine in dorsal and ventral hippocampus. II. Effects of H sub(1) and H sub(2) histamine antagonists on exploratory behavior in male rats

The effects on Hole-Board behavior of histamine (HA) microinjected into different parts of the hippocampus and the effects of pyrilamine (PYR, an H sub(1)-histamine antagonist), ranitidine (RAN, an H sub(2)-histamine antagonist) or alpha -fluoromethyl-histidine ( alpha -FMH, an irreversible inhibitor of the HA synthesizing enzyme) injected into the hippocampus on behavior were studied. The present results support the hypothesis that HA in hippocampus may be exerting a regulatory role on behavior by interaction with H sub(1) and H sub(2) receptors.