Action of 6-hydroxydopamine on lamb sympathetic ganglia, vas deferens and adrenal medulla: a combined histochemical, ultrastructural and biochemical comparison with the effects of reserpine.
1. The effects of a single dose of 6-hydroxydopamine (6-OHDA) compared with those of chronic reserpine treatment were studied in lamb sympathetic neurones and adrenal medulla by a combination of fluorescence histochemistry, electron microscopy and radiochemical assay.2. In sympathetic ganglia, 6-OHDA produced a rise in noradrenaline concentration within 24 h, and falls in tyrosine hydroxylase and monoamine oxidase activities, whereas reserpine caused a fall in noradrenaline, a rise in tyrosine hydroxylase activity and no change in monoamine oxidase activity. The fluorescence of intra- and postganglionic axons increased greatly within 24 h of 6-OHDA, and there was a corresponding accumulation of large dense-core vesicles within many axons whose neurotubules were disrupted. The changes were almost reversed after 3 weeks.3. In the vas deferens, the concentration of noradrenaline and tyrosine hydroxylase and monoamine oxidase activities had all fallen 24 h after 6-OHDA treatment and had started to recover 3 weeks later. In the adrenal medulla, 6-OHDA did not alter NA concentrations but increased tyrosine hydroxylase activity whereas reserpine depleted noradrenaline and increased tyrosine hydroxylase activity.4. The changes produced in sympathetic ganglia by 6-OHDA may be due both to a direct action on the axoplasmic transport of noradrenaline containing vesicles and indirectly to the reaction of the neurones to loss of the integrity of their axons.
D000313:Adrenal Medulla / Q000032:analysis / Q000033:anatomy & histology / Q000187:drug effects*; D000818:Animals; D005453:Fluorescence; D005725:Ganglia, Autonomic / Q000032:analysis / Q000033:anatomy & histology / Q000187:drug effects*; D008297:Male; D008854:Microscopy, Electron; D006899:Mixed Function Oxygenases / Q000032:analysis; D008995:Monoamine Oxidase / Q000032:analysis; D009638:Norepinephrine / Q000032:analysis; D010627:Phenethylamines / Q000494:pharmacology*; D012110:Reserpine / Q000494:pharmacology*; D012756:Sheep; D014443:Tyrosine / Q000032:analysis; D014649:Vas Deferens / Q000032:analysis / Q000033:anatomy & histology / Q000187:drug effects*
D010627:Phenethylamines; D014443:Tyrosine; D012110:Reserpine; D006899:Mixed Function Oxygenases; D008995:Monoamine Oxidase; D009638:Norepinephrine