[Regulation of the superprecipitation of an actomyosin-like protein from the brain by glycolipids].

The optimal conditions (ionic strength, pH, Mg2+ and ATP concentrations) for nephelometric determination of the superprecipitation reaction of the actomyosin-like protein (AMLP) from ox brain cortex are described. At low ionic strength (0.1 M KCl, 200 micrograms of protein, pH 6.

[Contractile proteins of nerve endings as a possible target of the presynaptic action of tetanus toxin].

Tetanus toxin (TT) in a dose of 0.25--250 DLM/ml inhibits the superprecipitation reaction of actomyosin-like protein (AMLP) of the bovine brain in response to Mg-ATP addition. Gangliosides of the bovine brain exert a similar action.

[Interaction between actin like protein of the brain and isolated synaptic vesicles].

It was shown that Mg-ATP increased light diffusion in the suspension of synaptic vesicles (SV) of the rat brain in the presence of actinolike protein (ALP) of the bovine brain (the superprecipitation test). ALP enhanced the activity of the SV Mg-ATPase and increased endogenic moradrenaline release from the bovine hypothalamus SV, eliminated by cutochalazine B. Glycolipids (gengliosides and cerebrosides) inhibited the superprecipitation test.

[Isolation and properties of an actomyosin-like protein from bovine brain glial cells].

Actomyosine-like protein (AMLP) was isolated from the enriched glial fraction of the bovine brain cortex. The AMLP yield constitutes 0.05% of protein in the glial cells.

[Effect of tetanus toxin and colchicine on synaptic membranes of rat cerebral cortex].

It was shown that purified tetanus toxin did not influence the activity of the Na, K-ATP-ase fractions of the synaptic membranes of the rat cerebral cortex, it had no effect on the inhibition of Na, K,-ATP-ase under electrical stimulation of the synaptic membrane suspension, or the GABA--3H binding by the synaptosomes in vitro. Tetanus toxin (400--4000 DLM) and colchicine (1 mM) induced a decrease of osmotic sensitivity of the nerve endings. Colchicine in low concentrations (10(-5)-10(-3) M) failed to influence Mg-and Na, K-ATP-ases, but considerably inhibited both ATP-ases at higher concentrations.

[The effect of psychotropic substances on synaptosomal uptake of gamma-aminobutyric H3-acid and the activity of Na,K-ATPase].

The centrally acting drugs belonging to different groups--fluphenazine, trifluperidol, phthoracyzine, imipramine, diazepam, apomorphine, fentanyl, diphneylhydantoin, nonachlazine displayed in vitro an inhibitory effect on the uptake of gamma-aminobutyric acid by rat brain synaptosomes. A decrease in the activity of synaptosomal Na,K-ATPase was found in most cases. Drugs that failed to alter GABA uptake were as a rule found to be ineffective in relation to the enzyme activity (carbidine, morphine).