Depletion of somatostatin-like immunoreactivity in the rat central nervous system by cysteamine.
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.
D000818:Animals; D002490:Central Nervous System / Q000187:drug effects* / Q000378:metabolism; D002850:Chromatography, Gel; D003543:Cysteamine / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D006801:Humans; D007031:Hypothalamus / Q000187:drug effects / Q000378:metabolism; D051381:Rats; D011919:Rats, Inbred Strains; D013004:Somatostatin / Q000032:analysis / Q000276:immunology / Q000378:metabolism*
D013004:Somatostatin; D003543:Cysteamine