THE MACROPHAGE AS A SITE OF EXTRANEURONAL UPTAKE AND O-METHYLATION OFNOREPINEPHRINE

Macrophages present in cervical lymph nodes are shown to be the cellul ar site of both the extraneuronal uptake of norepinephrine (NE) and ca techol-O-methyltransferase (COMT). The localization of COMT was determ ined by immunocytochemical methods showing COMT-specific immunoreactiv e deposits in macrophages. The extraneuronal site of NE uptake was det ermined by histochemical fluorescence. A pronounced granular green flu orescence was present in the cytoplasm of macrophages following NE upt ake. Our results suggest that macrophages may provide a model system f or the study of both the extraneuronal transport and O-methylation of NE.