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After the intraperitoneal administration of ⁸⁶RbCl to mice in a dose of 0.5 mM/kg, the maximum levels in the liver and kidneys were attained in the first hour, but in the brain not for 24 h. The Rb⁺ half-time in the tissues was about 170 h. With peroral administration, tissue rubidium levels at 3 days were higher than after intraperitoneal injec-tion. Rubidium did not affect sodium levels in rats, but lowered potassium levels. Cesium led to an increase in tissue rubidium levels, while diuretics had not significant effect on them. The erythrocyte saturation rate was correlated to the species, but there were no differences between young and old individuals, or between healthy subjects and manic-depressive patients. Rubidium was not displaced from the erythrocytes by the presence of high potassium concentrations in the medium.

Sumraary: In an attempt to establish a radioimmunoassay (RIA), imipramine and amitriptyline immunogens were prepared; desmethyl derivatives were converted into hemisuccinates, conjugated with bovine serum albumin and used for rabbit immunization. [ 3 H]Amitriptyline (4.3 TBq/mmol) and [ 3 H]imipramine (2.9 TBq/mmol) were prepared by catalytic dehalogenation or reductive alkylation. Dibenzazepines and dibenzcycloheptanodienes were determined in biological fluids by a direct method without deproteinization (lower detection limit of 0.5 μg • l" 1); using high-yield methods they were extracted from cell membranes. Assay of tricyclic antidepressants in humans showed that these substances disappear from plasma much earlier than from cell membranes. Dissociation of the antidepressants bound to cell membranes *is slow and their plasma concentrations are not influenced by Standing for 2 h at 4 °C. During preparing the membranes for binding studies these substances are not removed, and they may affect the results of the binding studies.

The authors studied the effect of rubidium, lithium and cesium on the ATPase system and c-AMP protein kinase in brain. They demonstrated that rubidium could replace potassium in the Na⁺K⁺-ATPase system, whereas lithium and cesium had no effect on this enzyme activity in the absence of potassium. K⁺-dependent ATPase was activated by even low rubidium concentrations; lithium and cesium inhibited it. None of three (rubidium, lithium and cesium) affected c-AMP protein kinase.