[Changes in serotonin and histamine levels in human blood after 370-day anti-orthostatic hypokinesia]. / Izmenenie soderzhaniia serotonina i gistamina v krovi cheloveka pod vliianiem 370-sutochnoi antiortostaticheskoi gipokinezii.

Ten healthy men took part in a 360-day antiorthostatic hypokinesia study. They were subdivided into two equal groups that differed in terms of time when they started using counter-measures: Group A began exercising on the first day of exposure and Group B on bed rest day 120. As compared to the baseline, the test subjects showed a decrease of serotonin (Ser) and histamine (HA). The only exception was HA increase on bed rest day 50 in the Group A subjects. The difference in Ser and HA concentrations in Group A and B subjects was insignificant on bed rest days 110 through 350. On the 60th day after the study Ser and HA concentrations did not yet return to norm. These observations indicate that changes in the serotonin- and histaminergic systems cannot be compensated within the above period of time.

[Use of erythrocytes for the intravital evaluation of adrenoreceptor function]. / Ispol'zovanie éritrotsitov krovi dlia prizhiznennoi otsenki funktsional'nogo sostoianiia adrenoretseptorov.

Administration of guanethidine (50 mg/kg) decreased the noradrenaline content in adrenergic neurons which led to an augmentation of the effector organ's adrenoreactivity in rats. The affinity of the erythrocytes' beta-adrenoreceptors to propranolol was enhanced and the parameters of their binding the fluorescent probe were changed. The data obtained suggest the possibility of using the erythrocytes for in vivo estimation of functional state of adrenoreactive system in animals and humans.

[Study of the beta-adrenoreceptive function of the erythrocyte membrane of the guinea pig using spectral luminescence analysis]. / Issledovanie beta-adrenoretseptivnoi funktsii membran éritrotsitov morskoi svinki s pomoshch'iu spektral'nogo liuminestsentnogo analiza.

The binding of DSM fluorescent probe with erythrocyte membranes in conditions of the organism high and low adrenoreactivity was studied in guinea pig. The dependence of DSM binding on the level of adrenoreactivity was shown by probe luminescence in the range of 615 nm. Specific and unspecific types of the DSM bindings with erythrocyte membranes were revealed. In high adrenoreactivity, an increase of specific binding places (Nsp) and a decrease of specific binding constant (Ksp) were found whereas in low adrenoreactivity the Nsp decreased and the Ksp increased.

[The use of fluorescence probes in the study of the beta-adrenoreceptor function of human erythrocytes]. / Primenenie fluorestsentnogo zonda dlia izucheniia beta-adrenoretseptivnoi funktsii éritrotsitov krovi cheloveka.

Possibility of making use of fluorescent probe 4-(p-dimethyl aminostyril)-1-methyl pyridinium p-toluene-sulphonate (DSM) for observing the interaction of beta-adrenoactive substances (adrenaline and propranolole) and specific receptors of human blood erythrocytes has been studied. Two types of DSM bindings with erythrocyte membranes have been revealed--specific and non-specific. It has been found that DSM reacts selectively to preliminary influence of beta-adrenoactive substances: antagonist propranolole diminishes both specific and nonspecific bindings and agonist adrenaline increases specific binding with the membrane erythrocytes. The conclusion is made as to possible use of DSM probe for investigating beta-adrenoreceptive function of the cell membranes.

[Hydrazine derivative modification of the activity of brain mitochondrial monoamine oxidases]. / Modifitsirovanie aktivnosti mitokhondrial'nykh monoaminoksidaz mozga nekotorymi proizvodnymi gidrazina.

Treatment of bovine brain stem mitochondria with hydrazine derivatives, which inhibited the monoamine oxidase activity (substrate: 5-hydroxytryptamine), was accompanied by appearance of the properties to deaminate histamine and cadaverine at a high rate. The same phenomenon was observed in vivo after treatment of mice with the hydrazine derivatives. The dramatic increase in histamine deaminating activity in brain was accompanied by a decrease in the tissue concentration of histamine. The hydrazine derivatives are considered as prooxidants stimulating via a free-radical mechanism lipid peroxidation in methyloleate solutions and in biomembranes (ref. 5) and causing qualitative alteration (transformation) in catalytic properties of monoamine oxidases of the tyre A, which acquire the histamine deaminating activity. A certain correlation was noted between the prooxidant effect of the hydrazine derivatives and the modification of catalytic properties of the membrane bound monoamine oxidases of brain mitochondria in vitro and in vivo.

[Modification of mitochondrial monoamine oxidase activity by certain amine inhibitors]. / Modifitsirovanie aktivnosti mitokhondrial'nykh monoaminoksidaz nekotorymi aminnymi ingibitorami.

Monoamine oxidase inhibitors /trans-2-phenylcyclopropylamine, pyrazidol, phenharmane/ belonging to the category of primary or secondary amines, in the molecule of which/ after dehydration/ formation of an azomethine bond is possible, modified the activity of membrane bound bovine brain monoamine oxidases inhibiting the deamination of serotonin and, at the same time, causing appearance of or significant increase in cadaverine--or histamine--deaminating properties. This modification was not caused either by primary amines /amphetamine, GABA/ which are not potent monoamine oxidase inhibitors or by the amines possessing strong monoamine oxidase inhibiting properties/pargylline, deprenyl, harmine/ but devoid of the potential property of forming an azomethine bond. In vivo trans-2-phenylcyclopropylamine, pyrazidol or phenharmane /contrary to amphetamine/ did modify the monoamine oxidase activity in brain of mice inducing the deamination of histamine and decreasing its tissue concentration.

[Effect of the antihistamine preparation, fencarol, and other quinuclidyldiarylcarbinols on tissue aminoxidase activity]. / Vliianie protivogistaminnogo preparata fenkarola i drugikh khinuklidildiarilkarbinoov ba aktivnost' tkanevykh aminoksidaz.

In experiments in vivo, the derivatives of quinuclidylarylcarbinol, possessing an antihistaminic activity, fencarol, its di(o-tolyl)- and di(o-methoxyphenyl)-derivatives activate histamine oxidative deamination by diaminoxidase of the rat lungs and increase the histamine tissue level. Quinuclidyl-3-dithienyl carbinol inhibits the activity of diaminoxidase, but decreases the histamine tissue level. On the contrary, dimedrol (diphenhydramine), pipolfen (promethazin), pyrilamine and cyproheptadin exerted no effect on the activity of diaminoxidase or the histamine tissue level. All the compounds studied did not alter oxidative deamination of the rat brain serotonin by monoamine oxidase or the serotonin content in brain tissues.

[Effect of D,L-malic acid dibenzylhydrazide on changes in the antioxidizing activity of lipids and monoamine oxidase activity in mouse organs]. / Izmenenie antiokislitel'noi aktivnosti lipidov organov myshei i aktivnosti monoaminokisdazy pri deistvii dibenzilgidrazida D,L-iablochnoi kisloty.

Administration of dibenzylhydracide of D,L-malic acid (inhibitor of monoamine oxidase) into animals caused not only inhibition but also transformation of the mitochondrial monoamine oxidase activity, which acquired the property to deaminate histamine. Effect of the monoamine oxidase inhibitor on the antioxidative activity of lipids from mouse liver and brain tissues was studied. Effect of the dose administered and of the period of its action after administration were characterized. Influence of the inhibitor on oxidation of methyloleate was also studied in a model system. The data obtained suggest that the transformation-producing effect of the substance was not related to its immudiate action on the enzyme molecule but was apparently due to its influence on the intensity of lipid peroxidation in membranes.

[Multiplicity of monoamine oxidase: inhibition of mitochondrial monoamine oxidase activity by isopropylhydrazide of D,L-serine]. / O mnozhestvennosti monoaminoksidaz: tormozhenie izopropilgidrazidom D,L-serina monoamikonsidaznoi aktivnosti mitokhondrii.

Isopropylhydrazide of D,L-serine (IHS) inhibits by 50% (at 37 degrees for 10 min) deamination of serotonin or beta-phenylethylamine by monoamine oxidases from bovine brain stem mitochondrial membranes at the 2.6 X X 10(-5) M or 9 X 10(-5) M, respectively. In order to inhibit by 50% the deamination of tyramine under the same conditions a considerably lower (2.5 X X 10(-6) M) concentration of IHS is required. Kinetic studies of inhibition of enzymatic deamination of all the three biogenic monoamines by IHS showed that the irreversible blocking of the monoamine oxidase activity is preceeded by formation of dissociating enzyme-inhibitor complexes. Values of the dissociation constants of these complexes measured (at 37 degrees) with serotonin, phenylethylamine or tyramine as substrates for estimation of the residual monoamine oxidase activity are 0.47; 0.13 or 0.023 mM, respectively. Significant differences are also found between thermodynamic and activation parameters characterizing both both steps of interaction between IHS and the monoamine oxidases of mitochondrial membranes in the experiments with serotonin, phenylethylamine or tyramine as substrates. The data obtained suggest the existence of different monoamine oxidases (or their active sites) catalyzing oxidative deamination of serotonin, phenylethylamine or tyramine in the fragments of mitochondrial membranes from bovine brain stem.

[Effect of serotonin and monoamine oxidase inhibitors on corneal anesthesia produced by celnovocaine and novocaine]. / Vliianie serotonina i ingibitorov monaaminaksidazy no anesteziiu rogovitsy, vyzyvaemuiu tselnovokainom i novokainom.

In experiments on guinea pigs it is shown that a preliminary intraperitoneal administration of monoamine oxidase inhibitors (MAOI) -- transamine (10 mg/kg) or malic acid benzyldihydrazide (50 mg/kg) antagonizes the local anesthetic action of celnovocaine (CC) and novocaine (NC). An analogous effect is also observed following instillation of transamine (a 0.1% solution) and malic acid benzyldihydrazide (a 0.23% solution) into the eye 10 minutes before administration of the anesthetic. Instillation of a 0.1% serotonin creatinine sulphate solution also antagonizes anesthesia produced by CC and NC, while MAOI potentiates the effect of serotonin.