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Objective To explore the effect of histamine on neurons in the hippocampal C1 area of SD rats and the behavior of depressive SD rats. Methods The effect of histamine on the discharge frequency of neurons in hippocampal C1 area was observed by in vitro extracellular recording of brain slices. The effect of endogenous histamine released to hippocampal neurons was observed through in vivo extracellular recording after the hypothalamus was electrically stimulated. In addition, the changes of motor activity and the ability of spatial memory of the rats with depression after microinjection of histamine into the hippocampal C1 area were observed by open-field test and Morris water maze test. Results The results of in vitro extracellular recording of brain slices showed that the hippocampal neurons were excited by histamine via H1 receptors rather than H receptors in a concentration dependent manner. The results of in vivo extracellular recording showed that endogenous histamine had a bidirectional effect, which means a short-term excitatory effect followed by a long-term inhibitory effect on the hippocampal neurons. After injected with histamine in the hippocampal C1 area,
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Objective To research the role of hypothalamocerebellar histaminergic projections in somatic‐visceral integration of rats .Methods A total of 120 SD rats were randomly divided to 6 groups :group A - F ;which separately microinjected saline (group A) ,triprolidine(selective antagonist of H1 receptor ,group B) ,2‐PyEA(selective agonist of H1 receptor ,group C) ,ranitidine (selective antagonist of H2 receptor ,group D) ,dimaprit (selective agonist of H2 receptor ,group E) and histamine (group F) to the deep nuclei of rats .The abilities of rats somatic‐visceral integration were observed when hypothalamocerebellar histaminergic pro‐jections were obstructed or enhanced compared to group A .Results The somatic‐visceral integration of rats were obstructed obvi‐ously in group D and enhanced in group E & group F compared to group A ,while group B and group C had no differences compared to group A .Conclusion Hypothalamocerebellar histaminergic projections play a key role in somatic‐visceral integration through the way of H2 receptors .