Premium
Axonal Transport of Slow Component a in Sciatic Nerves of Hypo‐and Hyperthyroid Rats
Author(s) -
Sidenius Per,
Nagel Poul,
Larsen JØrn Rolighed,
Boye Niels,
Laurberg Peter
Publication year - 1987
Publication title -
journal of neurochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.75
H-Index - 229
eISSN - 1471-4159
pISSN - 0022-3042
DOI - 10.1111/j.1471-4159.1987.tb02437.x
Subject(s) - sciatic nerve , axoplasmic transport , component (thermodynamics) , neuroscience , anatomy , medicine , biology , physics , thermodynamics
: Axonal transport of slow component a was studied in dorsal root afferents of the sciatic nerves of hypo‐and hyperthyroid rats. Three experimental groups of rats were made hypothyroid at the age of 12 weeks by the administration of 131 I. From the age of 22 weeks to the end of the study, the groups were treated with daily subcutaneous injections of thyroxine in various doses to make them hypo‐(0 ug/100 g), normo‐(1 ug/100 g), and hyperthyroid (6 ug/100 g), respectively. The hypothyroid group had a moderate thyroid hormone deficiency (a serum triiodothyro‐nine level of 0.19 ± 0.10 nmol/L and a heart/body weight ratio of 1.87 ± 0.09 g/kg at time of killing compared with 0.60 ± 0.09 nmol/L and 2.18 ± 0.06 g/kg, respectively, for the control group). The hyperthyroid group was severely deranged, with serum triiodothyronine being 3.30 ± 0.37 nmol/L and a heart/body weight ratio of 3.11 ± 0.16 g/kg. The hypothyroid rats shov/ed a reduction in mean velocity for the transport of slow component a (0.80 ± 0.07 mm/day compared with 0.91 ± 0.05 mm/day in the controls). The width of the wave of activty was smaller for the hyperthyroid group than for the control group (6.6 ± 0.7 mm compared with 8.1 ± 1.2 mm), suggesting an increased clearance of the axonally transported activity in the proximal axon. A decrease in transport of slow component a in hypo‐thyroidism may be the explanation of peripheral neuropathy with axonal degeneration occasionally seen in patients with severe myxoedema.