[An inhibitor of nerve cell membrane Na,K-ATPase. Isolation and general characteristics].

A reversible inhibitor of Na,K-ATPase (M(r) approximately 190 Da, Ki = 4 x 10(-7) M) has been isolated from rat brain tissue. The inhibitor has no structural analogs among currently known endogenous inhibitors of Na,K-ATPase.

[Anomalous excretion of glycosaminoglycans in patients with syringomyelia].

Glycosaminoglycan (GAG) urine concentrations in syringomyelia patients were much higher than in healthy subjects from January to September. Maximum values of GAG excretion (twice as much as control) in affected patients were observed in spring and summer (from March to July). The results suggest that syringomyelia is accompanied by disorders in GAG connective tissue accumulation.

[Glycosaminoglycans in syrinogomyelia].

Excretion of glycosaminoglycans (GAG) with urine was 2.7-fold decreased in patients with syringomyelia as compared with healthy persons. Patterns of GAG decreased excretion are genetically determined and inherited as dominant features.

[Products of alkaloid oxidation by a blood plasma hemeprotein].

Hemoprotein isolated earlier from blood plasma was shown to inactivate alkaloids by transforming them into N-oxides.

[Plasma enzymes inactivating alkaloids].

It was shown that rat blood plasma contains two enzymes that inactivate alkaloids by transforming them into N-oxides. Both enzymes are hemoproteins: one of them consists of three different polypeptides with Mr of 63, 35 and 12 kD, while the other one is a single polypeptide with Mr of 73 kD. Both enzymes exhibit cooperative properties.

[Blood protein-inactivating atropine].

A xenobiotics-inactivating hemoprotein related to the class of pharmacologically active compounds (cholinolytics) was detected in rat blood. Ammonium sulphate fractionation, DEAE cellulose chromatography and gel filtration on Sephadex G-75 resulted in 750-fold purification of the protein; its Mr = 73 000-80 000. Multiple injections of the protein to experimental animals led to a 2-3-fold increase of the protein content in the blood.

[Intracellular hormonal function of acetylcholine and noradrenaline: the regulation of the catalase level in liver cells].

The injection of acetylcholine (15 to 150 micrograms/100 g) to rats or preincubation in the hepatic homogenate with acetylcholine (10(-6) to 10(-3) M) induces a decrease in the catalase activity, mainly in its bound form. Acetylcholine effect does not manifest in the presence of actinomycine D and puromycine. Noradrenaline injection to animals (1.

[Endogenous activators and inhibitors of Na, K-ATPase induced by acetylcholine].

Preincubation of rat brain homogenates with acetylcholine (ACh) in concentrations of 10(-3)-10(-5) M for 60 minutes produces an essential increment (15-30%) in activity of microsomal Na, K-ATPase. Analogous effect was exerted by the acetylcholinesterase inhibitor eserine (10(-5)-10(-6) M). Acetylcholine has no effect in the presence of actinomycin D.

[Regulation of acetylcholinesterase level in microsomes of neurons by acetylcholine and cyclic nucleotides].

In a cell-free system containing isolated nuclei and microsomal-cytoplasmic brain fraction there takes place a spontaneous puromycin-sensitive increase in acetylcholinesterase (AChE) activity of microsomes. As a result of preincubating the system with acetylcholine (ACh) (10(-6)-10(-3) M), AChE activity of microsomes was found to be increased, reaching the maximal value at an ACh concentration of 10(-5) M (25% during 60 min incubation). The effect of ACh was not detectable in the presence of actinomycin D and puromycin.

[Noradrenaline as a RNA and Na K ATPase biosynthesis regulator in the neurons].

Noradrenaline (10(-5)M) inhibits the summary RNA synthesis in isolated neurone nuclei. In the presence of the dissolvable cytoplasmic fraction noradrenaline effect is transformed: 3H-UTP inclusion into RNA is activated. Similar results were seen in experiments with adenosine-3',5'-cyclophosphate and previously with acetylcholine.

[Activation of Na, K-ATPase from nerve cell microsomes by acetylcholine in a model system].

Microsomal Na, K-ATPase is activated by acetylcholine (5 x 10(-6)--10(-5) M) in a cell-free system including neuronal nuclei and the microsomal--cytoplasmic fraction. No enzyme activation by acetylcholine occurs in the presence of puromycin, actinomycin D and ribonuclease or upon removal of the nuclear or microsomal--cytoplasmic fraction from the system. After preincubation with acetylcholine the membranes reveal a better capacity for phosphorylation by [gamma-32P]ATP and dephosphorylation in the presence of ADP and Na+.

[RNA synthesis in the isolated nuclei of nerve cells treated with acetylcholine].

Acetylcholine modified the incorporation of radioactive precursors 3H-uridine-5-triphosphate, 14C-uridine and 14C-cytidine in RNA of nuclei isolated from the rat brain. This modification has two tendencies: either the activation or the suppretion. The character of the nuclear reaction depends upon the season and animal population.

[Correlation of Na,K-ATPase activity and protein synthesis in nerve cell membranes exposed to acetylcholine].

Acetylcholine (10(-6)--10(-3) M) added to the rat brain homogenate increased that activity of microsomal Na, K-ATPase and (14C)-amino acid incorporation in microsomal proteins. Actinomicin D (5.10(-5) M) eliminated the effect of acetylcholine.