[The excitatory effects of histamine on cerebellar cortical Purkinje cells in the rat].
ABSTRACT The effects of histamine on Purkinje cells (PCs) in lobule X of cerebellar cortex were investigated in rat cerebellar slices. Histamine elicited PCs' responses predominately excitatory (94.4%, 51/54), only few inhibitory (5.6%, 3/54). The excitatory response could not be abolished by perfusing the slices with low Ca2+/high Mg2+ medium. The excitatory response of PCs to histamine could be blocked by histamine H2 receptor antagonist ranitidine, but not by H1 receptor antagonist triprolidine readily. These results suggest that histamine exerts an excitatory effect on the PCs via H2 receptors. Presumably, hypothalamo-cerebellar histaminergic fibers participate in the regulation of somatic and non-somatic functions of the cerebellum.
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ABSTRACT: Although a number of neuromodulators influence the cerebellar circuitry, their functions remain largely unknown. By reviewing and combining results from data-driven and theory-driven studies, we attempt to provide an integrated systems view of cerebellar neuromodulation. First, we review the short- and long-term effects of neuromodulators on the cerebellar circuitry. Second, we review recent theories of the cerebellum and show that a number of modulatory signals are needed for powerful cerebellar learning and control. Finally, we attempt to match each theoretically derived modulatory signal with a specific neuromodulator. In particular, we propose that serotonin controls the 'responsibility' of each cerebellar unit (or microcomplex) in cerebellar learning and control; norepinephrine gates unsupervised learning in the cerebellar cortex; dopamine enhances goal-oriented cerebellar learning; and, finally, acetylcholine controls the speed of supervised learning in Purkinje cells.Brain Research Reviews 04/2004; 44(2-3):103-16. · 10.34 Impact Factor