Metabolic aspects of the synthesis and intra-axonal transport of noradrenaline storage vesicles.

Abstract

1. Constricted cat hypogastric nerve/inferior mesenteric ganglion preparations have been maintained for 24 hr in vitro, in either test-tubes or a two compartment box, and used to study the roles of energy metabolism, protein synthesis and calcium ions in the synthesis and transport of noradrenaline storage vesicles in sympathetic neurones.2. When preparations were incubated so that the nerve trunks but not the ganglia were made anoxic, dense-cored vesicles lost their store of noradrenaline and did not accumulate above the ligature. This was accompanied by profound ultrastructural damage to the nerves.3. When in contact with the ligated nerve trunks, sodium fluoride inhibited the intra-axonal movement of dense-cord vesicles but did not deplete them of their stored noradrenaline. When sodium fluoride and pyruvate were present in the medium bathing the nerve trunks the movement of noradrenaline storage vesicles was unaffected.4. Whilst a reduction of the calcium ion concentration in the incubation medium and the inhibition of protein synthesis by cycloheximide prevented the synthesis of dense-cored vesicles in the neuronal perikaryon they had no effect on the movement of preformed dense-cored vesicles along non-myelinated axons.