Kinetics of 137cesium in cerebral structures and blood

The old clinical use of cesium in epilepsy expresses a relation of this metal with the central nervous system. Two groups of male Wistar rats of 200 g were administered single doses of 50 μCi intravenously for blood kinetics and 2μCi137CsCl in each lateral ventricle of the brain for the kinetics in the cerebral structures, respectively. In both cases under ether anesthesia. Blood samples of IV gouts were weighed, and cerebral structure hypothalamus, hypocampus, striatum, cortex, cerebellum, mesencephalon and medulla oblongata dissected, cleaned, washed, dried, weighed, and in both cases cpm of the samples evaluated submitting it to the gamma radiations detector.In blood experimental values of the 137CsCl kinetics are expressed and applying the retroprojection method; parameters and constants are obtained. t1/2 alpha = 0.0358 h and t1/2 beta = 6.7159h. In tables the equations of the alpha and beta phases are expressed. In blood after the rapid diminution of the radioactivity in the first 5 min the equilibrium phase is reached in 30 min afterwards, and the values remain almost the same 4h after the injection and cesium is slowly eliminated by the rat. Cerebral structures after its intracerebroventricular application show that cesium has a great uptake velocity, it is rapidly incorporated by hypothalamus and after by cortex, hypocampus, striatum, mesencephalon and medulla oblongata, the two last showing the slower incorporation. After 24h the cesium radioactivity declines slowly and progressively.