Enkephalin containing peptides in the peripheral sympathetic nervous system

The processing pathway of enkephalins along the sympathetic neuron was studied. While in vasa deferentia terminal parts of peripheral sympathetic neurons are found, sympathetic ganglia contain the cell bodies of these neurons. Biochemical evidence was obtained for the colocalization of met-enkephalin and noradrenaline in large dense-cored vesicles of sympathetic neurons of bovine vasa deferentia and bovine ganglia stellata. Acetic acid extracts of these tissues were analysed by a combination of chromatography, proteolytic digestion with trypsin and carbonxypeptidase B and specific radioimmunoassays. High molecular weight species of enkephalin containing peptides were detected in ganglia stellata. In contrast with the ganglia, only low molecular weight enkephalin containing peptides could be found in the vasa deferentia. When these peptides extracted from vasa deferentia were further analysed on reversed phase fast protein liquid chromatography, the met- to leu-enkephalin ratio was found to be 4.8 to 1, which is close to the 4 to 1 ratio found in the proenkephalin precursor. After digestion with trypsin and carboxypeptidase B, met-enkephalin immunoreactivity appeared in fractions probably containing met-enkephalin-arg-6-phe-7, met-enkephalin-arg-6-gly-7-leu-8 and peptide E.