Influence of lithium on the cellular environment.

In order to study the influence of lithium on the cellular environment, we conducted research in multiple experimental models: groups of rats with normal cerebral excitability and groups susceptible to audiogenic convulsion, rat neuroglia cultures and perfusion of dog isolated head. We assumed blood composition to be a good indicator of cell environment composition. Blood serotonin level differs in the two groups of animals. Lithium induces a decrease of blood serotonin and an increase of amine concentration in some of the cerebral regions of rats susceptible to audiogenic convulsions. Inverse effects occur in rats with normal cerebral excitability. In the perfused, isolated head of a dog, lithium immediately decreases blood serotonin level. Na and water have a diminished metabolization during the first 24 hrs. in both animal groups. Decrease in metabolization is somewhat greater in hyperexcitable animals. Within 48 hrs. after lithium injection, there is an increase of Na metabolization, probably determined by its storage in the interstice. Renal elimination of K decreases under the influence of lithium 48 hrs. after administering one dose of lithium. Lithium induces, immediately after injection, a decrease of blood Na concentration in the efferent flow of the jugular vein of a perfused dog head. When used in cell cultures, lithium (2 mM concentration) stimulates glial cells division (astrocytes, oligodendrocytes), increases their growth and aging rates. The effects of lithium may be due to its toxicity. Therefore, lithium alters the composition of the cellular environment depending on dose and on the state of the body.