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Electron and confocal microscopy, using immunocytochemical methods, was employed to assess osmotic water permeability of the frog (Rana temporaria) urinary bladder during transcellular water transport, induced by antidiuretic hormone (ADH) or by wash-out of autacoids from serosal, ADH-free Ringer solution. The increase of osmotic water permeability of the urinary bladder was accompanied by relevant ultrastructural changes, the most remarkable being: (1) the appearance of aggregates of intramembranous particles in the apical membrane of granular cells, and the extent of the membrane area covered by the aggregates proportional to that of the water flow; (2) redistribution of actin filaments in the cytoplasm of granular cells; judging from the anti-actin label density, the number of actin filaments in the apical region of cytoplasm was reduced by 2.5-4 times compared with normal; (3) a decrease in the total electron density of the cytoplasm due to the increased water content of granular cells.

Sixty-two children with nocturnal enuresis (43 boys, 19 girls aged 6-15 years) were treated with either desmopressin (Adiuretin-SD) (n = 32) or sodium diclofenac (n = 30). Desmopressin was effective in 85% of children and diclofenac in 33%. In children with primary nocturnal enuresis, the glomerular filtration rate was normal, whereas diuresis and solute excretion during the night were increased. Compared with healthy children, the nightly excretion of sodium was elevated by 43.7% and magnesium by 58.4%. A high correlation was found between the free water reabsorption and solute clearance (P < 0.001) in children with nocturnal enuresis. Changes in kidney function in nocturnal enuresis appear to be due to a decrease in the water and ion reabsorption in the thick ascending limb of Henle's loop because of a changed regulation of ion transport in this part of the nephron. Administration of desmopressin or a decrease in prostaglandin production after diclofenac administration restores the ion and water transport in the kidney, which results in the disappearance of nocturnal enuresis. The results indicate a role of changes in regulation of ion transport in renal tubules in the pathogenesis of one of the forms of primary nocturnal enuresis.

A method of "thin slices" was developed for estimation of enzymatic activities in cells, in which relationship between structure elements was maintained and the cells were readily permeable for substrates. Activities of Na, K-ATPase and succinate dehydrogenase were markedly higher in thin slices than in homogenates; activities of choline esterase and lactate dehydrogenase were of the same value in both tissue preparations. As compared with controls, adrenalectomy caused a decrease in Na, K-ATPase activity in the tissue slices, activities of succinate- and lactate dehydrogenases were unaltered and the choline esterase activity was increased. Comparison of the enzymatic activities in homogenates and thin slices indicates that some contradictions in data on the effect of the adrenal cortex hormones on the activity of the enzymes involved in the ion transport porcesses are due mainly to unadequateness of the methods used.

Experiments are described on the dynamics of the renal excretion of water and electrolytes, osmotically active substances and osmotically free water during bed rest. In short-term experiments (up to 10-14 days) renal changes are mainly associated with haemodynamic disturbances and fluid redistribution, whereas in longer duration experiments (up to 50 days) they are brought about by metabolic changes.

During PAH excretion and 18 h after repeated PAH administrations to rats, renal cortical SDH activity was unchanged in comparison with untreated controls. On the other hand, 18 h after repeated administrations of 0.9% or 1.8% NaCl solution, SDH activity was decreased by about 20% in kidney cortex. In outer medulla SDH activity was decreased 18 h after all pretreatments. The decline of SDH activity was observed whenever an increased urinary Na excretion occurred, except that PAH was repeatedly administered. The probability is discussed that substrate-induced stimulation of the carrier system for weak organic acids is accompanied by an increase of mitochondrial activity in kidney cortex.

In the course of evolution of the invertebrate gravity receptor endogenous intracellular mode of the otoliths formation (Coelenterata, Ctenophora) is changed for endogenous extracellular mode (Mollusca, Arthropoda). The intracellular otolith is represented by cristalline concretions whereas extracellular one may consists of many separate crystallic otoconia or one large spherolith. As a rule in all cases qualitative mineral composition is similar. Calcium is the main component of the otolith in invertebrates (as vertebrates) though magnesium, sodium and potassium also take place in the otolith formation.

Сердепные гликозиды с в 19-OM no-ложении молекулы оказались наиболее зффективными ингигиторами натриевого наоаса клеток кожи лягшки. Налицие ацетильного радикала увелицвало ингибирумуп способнность гликозида; агликон — оуабагенин оказался самым слабым инибитором.