Effect of hypothyroidism on rat peripheral nervous system.
The function and structure of the peripheral nervous system of Sprague-Dawley rats, 3 months after the induction of hypothyroidism by administration of N-propylthiouracil in drinking water, has been studied. The motor action potential amplitude of the caudal nerve showed a significant reduction (p < 0.001) when compared with an age-matched control group of animals. Computer-assisted morphometric analysis of sciatic nerves of hypothyroid rats showed normal distribution and density of myelinated fibers, and a normal axon/myelin ratio. Electron microscopy revealed only minor alterations in axons of myelinated fibers characterized by a dissolution of neurotubules. After two months of substitution therapy these effects were reversed. The present data suggest that early impairment of nerves induced by hypothyroidism is rare and could be related to metabolic alterations rather than to structural changes and is reversible with hormone treatment.
Department of Neurology, University of Milan, Istituto Scientifico S. Raffaele Hospital, Italy.
A
A
Quattrini
R
R
Nemni
P
P
Marchettini
R
R
Fazio
S
S
Iannaccone
M
M
Corbo
N
N
Canal
D000200:Action Potentials / Q000187:drug effects; D000818:Animals; D004576:Electromyography; D007037:Hypothyroidism / Q000139:chemically induced / Q000473:pathology / Q000503:physiopathology*; D007382:Intermediate Filaments / Q000648:ultrastructure; D008297:Male; D008870:Microtubules / Q000187:drug effects / Q000648:ultrastructure; D009046:Motor Neurons / Q000187:drug effects; D009431:Neural Conduction / Q000187:drug effects; D010525:Peripheral Nerves / Q000473:pathology / Q000503:physiopathology*; D011441:Propylthiouracil; D051381:Rats; D017207:Rats, Sprague-Dawley; D012584:Sciatic Nerve / Q000187:drug effects; D014284:Triiodothyronine / Q000097:blood / Q000494:pharmacology
D014284:Triiodothyronine; D011441:Propylthiouracil