Beta-adrenergic modulation of GABAergic inhibition in the deep cerebellar nuclei of F344 rats.

The presence of norepinephrine (NE) and NE activated cells, in the deep cerebellar nuclei (DCN) of male F344 rats, was investigated using immunohistochemistry and electrophysiology, during iontophoresis of the beta-adrenergic agonist isoproterenol (ISO). During extracellular electrophysiology, GABA was iontophoretically applied to the cell and ISO was then co-applied in an attempt to modulate the GABAergic inhibition of cell firing in the DCN. Immunohistochemistry was used to detect tyrosine hydroxylase (TH) positive fibers in the DCN. Isoproterenol modulated GABAergic inhibition in 51% of the DCN cells recorded from. In addition, TH-positive fibers that appeared to make contact with DCN cells were found. Therefore, this study demonstrated that functional NE receptors exist in the DCN and NE appears to be present in fibers therein.