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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
Author(s) -
CHEAH T. B.,
GEFFEN L. B.,
JARROTT B.,
OSTBERG A.
Publication year - 1971
Publication title -
british journal of pharmacology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.432
H-Index - 211
eISSN - 1476-5381
pISSN - 0007-1188
DOI - 10.1111/j.1476-5381.1971.tb07139.x
Subject(s) - reserpine , adrenal medulla , tyrosine hydroxylase , vas deferens , medicine , endocrinology , monoamine oxidase , hydroxydopamine , chemistry , tyrosine 3 monooxygenase , medulla , monoamine neurotransmitter , catecholamine , biology , serotonin , dopamine , biochemistry , enzyme , dopaminergic , receptor
Summary1 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.