RELEASE OF NOREPINEPHRINE FROM ORGAN-CULTURED SUPERIOR CERVICAL-GANGLIA - EFFECTS OF THE NOREPINEPHRINE UPTAKE INHIBITOR XYLAMINE

  • 1 January 1983
    • journal article
    • research article
    • Vol. 225  (3) , 623-629
Abstract
After preloading with [3H]norepinephrine (NE), organ-cultured rat superior cervical ganglia released increased amounts of [3H]NE when incubated with depolarizing K+-induced release was Ca2+-dependent, whereas tyramine- and amphetamine-induced release were not. Analysis of the released radioactivity by high-pressure liquid chromatography showed that these releasing stimuli caused primarily an increase in NE release, with little increase in the release of NE metabolites. Incubation with 10 .mu.M xylamine, an irrevrsible inhibitor of NE uptake, caused a small increase in [3H]NE efflux, but no reduction in the endogenous NE and dopamine levels in superior cervical ganglia. After xylamine treatment, tryamine-induced release was greatly inhibited, whereas release by amphetamine and K+ was not. The neuronal uptake inhibitor desipramine (1 .mu.M), affected K+-, tyramine- and amphetamine-induced release in a manner similar to xylamine. Xylamine evidently is a very weak releasing agent in this tissue and its effects on other release processes are consistent with its action as a NE uptake inhibitor. Amphetamine-induced release appears not to require the NE uptake system for either the uptake of amphetamine, as shown by the accumulation of [3H]amphetamine, or the efflux of NE.