Preclinical and clinical studies with cysteamine and pantethine related to the central nervous system.

1. Cysteamine is formed by degradation of coenzyme A (CoA) and causes somatostatin (SS), prolactin and noradrenaline depletion in the brain and peripheral tissues. 2. Cysteamine influences several behavioral processes, like active and passive avoidance behavior, open-field activity, kindled seizures, pain perception and SS-induced barrel rotation. 3. Cysteamine has several established (cystinosis, radioprotection, acetaminophen poisoning) and theoretical (Huntington's disease, prolactin-secreting adenomas) indications in clinical practice. 4. Pantethine is a naturally occurring compound which is metabolized to cysteamine. 5. Pantethine depletes SS, prolactin and noradrenaline with lower efficacy compared to that of cysteamine. 6. Pantethine is well tolerated by patients and has been suggested to treatment of atherosclerosis. The other possible clinical indications (alcoholism, Parkinson's disease, instead of cysteamine) are discussed.