Cerebrospinal fluid norepinephrine alterations during electrical stimulation of cerebellar, cerebral surfaces in epileptic patients

Lumbar cerebrospinal fluid norepinephrine concentrations were determined by radioenzymatic assay in five epileptic patients receiving double-blind cerebellar stimulation and in three epileptic patients with subdural cerebral surface electrodes. Mean CSF norepinephrine levels were significantly elevated by chronic cerebellar stimulation and significantly depressed after intermittent cerebral cortical stimulation. Lumbar CSF cyclic adenosine monophosphate levels determined by radioimmunoassay were not significantly altered by either cerebellar or cerebral surface stimulation. Our study suggests that (1) electrical stimulation of the anterodorsal cerebellum in man evokes alterations in noradrenergic metabolism. Cerebellar stimulation-induced elevations in norepinephrine may inhibit cerebellar, cerebral, and spinal neuronal activity. In addition, (2) noradrenergic responses to brain surface stimulation may exhibit regional specificity, and (3) noradrenergic alterations evoked by cerebral surface stimulation may not mimic those induced in isolated brain preparations.