Journal of Neuroscience, Vol 2, 225-231, Copyright © 1982 by Society for Neuroscience
Depletion of somatostatin-like immunoreactivity in the rat central nervous system by cysteamine
SM Sagar, D Landry, WJ Millard, TM Badger, MA Arnold and JB Martin
Selective neurotoxins have been of value in providing a means for
specifically interfering with the actions of endogenous neurotransmitter
candidates. Others have shown cysteamine (CSH) to deplete the
gastrointestinal tract and hypothalamus of rats of immunoreactive
somatostatin, suggesting a toxic action of that compound directed against
somatostatin-containing cells. The present study further defines the
actions of cysteamine on somatostatin in the central nervous system. (CNS).
Cysteamine hydrochloride administered subcutaneously results in a depletion
of somatostatin-like immunoreactivity (SLI) in the retina, brain, and
cervical spinal cord of rats. The effect is demonstrable at doses of 30
mg/kg of body weight and above, occurs within 2 to 4 hr of a single
injection of the drug, and is largely reversible within 1 week. The mean
depletion of SLI observed within the CNS varies from 38% in cerebral cortex
to 65% in cervical spinal cord 24 hr following administration of CSH, 300
mg/kg of body weight, s.c. By gel permeation chromatography, all molecular
weight forms of SLI are affected, with the largest reductions in those
forms that co-chromatograph with synthetic somatostatin-14 and
somatostatin-28. These results indicate that CSH has a generalized, rapid,
and largely reversible effect in depleting SLI from the rat CNS.