The distribution of exogenously administered Li+, Rb+ and Cs+ in distinct mouse brain regions was studied as a function of time subsequent termination of a short-term daily treatment with these
alkali metal salts. The resulting distribution profiles were compared with that obtained from the corresponding endogenous
alkali metals. Endogenous Rb+ and Cs+ were readily measurable in all 6 brain regions studied compared to traces of measurable Li+. The Rb+ concentration was greater than that of Cs+. Short-term treatment with equal doses of the
alkali metals studied showed greater brain accumulation of Rb+ and Cs+ than Li+ with a prolonged brain regions preference for Cs+ storages as a function of time. Duration of
ethanol-mediated
narcosis was reduced from saline controls by pretreatment with RbCl or
CsCl as contrasted with prolongation by LiCl. The
narcotic dosage of
ethanol used reduced endogeneous Li+ and increased Cs+ levels in the cerebellum. This massive
ethanol dosage exerted little effect on the distribution of exogenously administered Cs+ with exception of the striatum which continued to show a high content of Cs+. This may have contributed to partial antagonism of
ethanol-depressant action and to restoring of motor function, i.e., rapid regaining of righting reflex. The results showed that Cs+ possessed longer
biological life time in the brain than Rb+ or Li+ which may be of therapeutic value, i.e., in the use of Cs
salts in treatment of
brain tumors and in conjunction with
psychoactive agents provided the respective chemotherapeutic and
antidepressant properties of
CsCl have been established.