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erfusing slices with histamine (1-100 μM) produced the rat rubral neurons an excitatory response (118/132, 89.4%). The histamine-induced excitation was not blocked by the low-Ca2+/high-Mg2+ medium (n=10), supporting a direct postsynaptic action of the amine. Histamine H2 receptor antagonist ranitidine effectively blocked the excitatory response of rubral neurons to histamine (n=26), but H1 receptor antagonist triprolidine did not (n=24). The excitatory effect of histamine could be mimicked by dimaprit, a highly selective H2 receptor agonist (n=24), and the dimaprit-elicited excitation of the rubral neurons could be blocked by ranitidine (n=16), but not by triprolidine (n=9). In addition, H1 receptor agonist 2-pyridylethylamine could not elicit rubral neurons any response (n=12). These results indicate that histamine excites RN neurons through H2 receptors and suggest that the histaminergic afferent fibers may play an important functional role in the sensorimotor integration through th |
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Keywords:Red nucleus; Histamine; Histamine receptors; Hypothalamo-rubral fibers |
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