ETHANOL INHIBITS THE UPTAKE OF EXOGENOUS NOREPINEPHRINE FROM THE EXTRACELLULAR-SPACE OF THE RAT CEREBELLUM

Rapid chronoamperometric recordings using nafion-coated carbon fiber e lectrodes coupled with pressure-ejection of drugs were used to investi gate the effects of ethanol on norepinephrine (NE)-containing nerve te rminals in the urethane-anesthetized Fischer 344 rat. Local applicatio n of ethanol from a double-barrel micropipette did not produce detecta ble changes in extracellular levels of NE in the rat cerebellar cortex . However, when ethanol was applied prior to local application of NE, it was seen to inhibit the uptake of NE from the extracellular space. These results were compared to the effects seen from the local applica tion of a known high-affinity uptake inhibitor, nomifensine. Nomifensi ne was found to inhibit the extracellular uptake of NE in rat cerebell er cortex similar to ethanol. Our results support the hypothesis that one effect of ethanol on the noradrenergic system of the rat cerebellu m is an alteration in the uptake of NE into NE-containing nerve ending s. In addition, the present data concerning ethanol-induced inhibition of NE clearance or uptake support our previous electrophysiological s tudies in which we found that ethanol can potentiate the modulatory ef fects of beta-agonists on GABA responses of cerebellar Purkinje neuron s.