[Tyrosine hydroxylase activity in two-dimensional monomolecular films]. / Aktivnost' tirozingidroksilazy v dvukhmernykh monomolekuliarnykh plenkakh.

The activity of a neurospecific enzyme of tyrosine hydroxylase (TH) in monomolecular films formed onto solid surface was studied. The data obtained show that the formation of two-dimensional films onto negative-charge surfaces by the Langmuir-Schafer technology does not lead to the inactivation of the enzyme. Neuroleptic trifluoperazine increased the activity of TH. Monomolecular films of TH may be used as a sensitive element of biosensors for primary monitoring of neuroleptic-like compounds.

[Enhanced resistance to emotional stress through the use of D-phenylalanine]. / Povyshenie ustoichivosti k émotsional'nomu stressu s pomoshch'iu D-fenilalanina.

Stress-protective action was studied of D-phenylalanine, having an ability to decrease destruction of endogenic enkefalins. In the experiments stability of the experimental (receiving D-phenylalanine) and control groups of male rats of August line to emotional stress was compared in conditions of immobilization stress by parameters of animals survival rate, adrenal glands hypertrophy development, involution of thymus, pathologic changes in lungs (abscesses development), ulcero-dystrophic disturbances in stomach, and also the activity and kinetic properties of enzyme tyrosin-hydroxylase in the hypothalamus were determined. It was shown that by several of the mentioned physiological parameters the D-phenylalanine significantly increased the animals stability to the emotional stress and decreased tyrosinhydroxylase activity which participates in activation of katecholaminergic processes.

Dopamine deficiency syndrome in children with a special reaction to treatment with levodopa preparations.

The authors describe the dopamine deficiency syndrome in children with the disease beginning during their first year and unusual dystonia symptoms resulting in total immobilization and speech loss. All symptoms of the disease can be eliminated by low doses of nakom but reappear on withdrawal of the drug. Tyrosine hydroxylase studies made on these patients at various stages of the disease showed a different pattern of enzyme activity from that observed in children with similar pathology failing to improve dramatically under nakom treatment.

[Effect of tuftsin and hydroxymethacil on tyrosine hydrolase of macrophages in chronic stress]. / Vliianie taftsina i oksimetatsila na tirozingidrolazu makrofagov pri khronicheskom stresse.

It has been established that rat peritoneal macrophages possess tyrosine hydroxylase activity which has been characterized by KM4, 2 microM, Vmax 30 nmole/min per mg of protein. After 15 days of electronociseptive stimulation almost all tyrosine hydroxylase activity has been established in the form which has tyrosine KM47.0 M and Vmax 18.6 nmole/min. per mg of protein. Immunostimulator hydroxymethacil++, at its intraperitoneal injections to stressed rats during 7 days induced the appearance of low-affinity form of tyrosine hydroxylase with KM270 microM and Vmax 27.8 nmole/min.per mg of protein. The same low affinity form of the enzyme has been established after injections of tuftsin which possesses immunostimulating properties.

[Regulation of tyrosine hydroxylase activity in the rat hypothalamus with gamma-aminobutyric acid]. / Reguliatsiia aktivnosti tirozingidroksilazy gipotalamusa mozga krys gamma-aminomaslianoi kislotoi.

It is established that GABA interacts with tyrosine hydroxylase through the allosteric site which is not identical to sites of tyrosine, DOPA, pterin cofactor, dopamine binding. This interaction is very significant in the GABA influence on the regulation of the tyrosine hydroxylase activity by presynaptic receptors. GABA is supposed to be able to cause dissociation of oligomeric forms of tyrosine hydroxylase.

[Dopamine deficiency syndrome in children with specific reaction to the treatment with levodopa preparations]. / Sindrom dofaminovoi nedostatochnosti u detei s osoboi reaktsiei na lechenie preparatami levodopy.

The authors describe the dopamine deficiency syndrome in children with the disease beginning during their first year and peculiar dystonia++ symptoms resulting in a total immobilization and speech loss. All the symptoms of the disease can be removed by low doses of Nakom and reappeared upon the drug withdrawal. Tyrosine hydroxylase studies performed in these patients at various stages of the disease showed an unusual pattern of the enzyme activity differing from that seen in children with similar pathology failing to improve dramatically under the Nakom treatment.

[Effect of beta-mercaptoethylamine on tryptophan hydroxylase activity in rat tissues]. / Vliianie beta-merkaptoétilamina na triptofangidroksilaznuiu aktivnost' v tkaniakh krys.

The ability of amine-producing tissues (liver tissue, small intestine, mast cells) of rats to synthesize 5-hydroxytryptophan in response to irradiation and their involvement in creation of endogenous radioresistance was studied. Administration of a thiol radioprotector beta-mercaptoethylamine resulted in alteration of kinetic properties of tryptophane hydroxylase expressed as a decrease in the optimal concentration of the substrate; this decrease was more distinct in liver and small intestine as compared with mast cells.

[Tyrosine hydroxylase of the blood leukocytes]. / Tirozingidroksilaza leikotsitov krovi.

Tyrosine hydroxylase activity has been established in blood plasma leucocytes of rat, cat and man. Tyrosine precursors and some nuclear erythroid cells. GFU-GM did hydroxylase activity in leucocytes shows the Km for tyrosine inhibited by high concentrations of L6 tyrosine (substrate inhibition), alpha-methyl-para-tyrosine dopamine. The kinetic properties of leucocyte tyrosine hydroxylase are qualitatively similar to the properties of brain tyrosine hydroxylase.

[Effect of butaclamol enantiomers on hypothalamic tyrosine hydroxylase in the rat brain]. / Vliianie énantiomerov butaklamola na tirozingidroksilazu gipotalamusa mozga krys.

The authors demonstrate stereospecificity of the action of butaclamol enantiomers on substrate inhibition of hypothalamic tyrosine hydroxylase (TH) and regulation of the tyrosine hydroxylase response by the presynaptic membrane (presynaptic receptors) of rat hypothalamus synaptosomes under membrane activation with dopamine. The effect of (+)-butaclamol on the substrate inhibition of TH was noticeable at a concentration of 10(-8)M, reaching a maximum at 10(-5)M. (-)-Butaclamol administered at the same concentrations did not influence the substrate inhibition of the enzyme. (+)-Butaclamol added to the incubation medium containing hypothalamic synaptosomes concurrently with dopamine (10(-5)M) completely blocked the regulatory action of the latter on TH, with this action mediated via presynaptic receptors. (-)-Butaclamol (10(-5)M) antagonized the action of dopamine under the same conditions. The data obtained indicate high stereo-specificity of butaclamol enantiomers as regards their effect on presynaptic regulation of TH, suggesting that elimination of the substrate inhibition of hypothalamic TH is a stereoselective effect of neuroleptics and can be a prognostically important criterion in the appraisal of compounds with potential neuroleptic activity.

[Stereospecificity of the effect of flupenthixol isomers on the substrate inhibition of brain tyrosine hydroxylase]. / Stereospetsifichnost' éffekta izomerov flupentiksola na substratnoe tormozhenie tirozingidroksilazy mozga.

Stereospecificity of the effect of neuroleptics on substrate inhibition of isolated brain tyroxine hydroxylase is shown. Flupentixole cis-isomer eliminates substrate inhibition of the enzyme. The effect is concentration-dependent and is well marked within the tyrosine concentration range 10-6-10-4 M. Flupentixole trans-isomer in the same concentrations has no effect on substrate inhibition of tyrosine hydroxylase. In the presence of cis-flupentixole, the reaction rate plotted against tyrosine concentration is a hyperbole with a plateau at 160-360 microM tyrosine. In the presence of trans-isomer, as in the control sample, the relationships between the reaction rate and tyrosine concentration are depicted by a curve with a maximum (at 110-140 microM tyrosine). Like ftorphenazine, flupentixole isomer fails to eliminate the inhibitory action of alpha-methyl paratyrosine, which indicates the interaction of neuroleptics with the tyrosine-binding site of the enzyme molecules in the noncatalytic centrer. It is suggested that the interaction of the neuroleptics with the regulatory area of tyrosine hydroxylase might by important in the molecular mechanism of their action.

[Central effects of the tetrapeptide tuftsin]. / Tsentral'nye éffekty ttrapeptida taftsina.

Under systemic administration tuftsin produces a marked influence on behavior and emotional reactivity in rats: enhances motor (vertical) activity, perception of pain stimulation and related aggressiveness and residual excitation. Activating effect is accompanied by an aggravation of the acquisition of passive avoidance reaction during single reinforcement. In vitro experiments revealed a direct inhibitory effect of tuftsin on the reaction rate of brain tyrosine hydroxylase activity. In vivo there was shown an increase in hypothalamic and especially striatal tyrosine hydroxylase activity. The data obtained indicate direct relationships between tuftsin central effects and the changes in brain catecholaminergic processes participating in the regulation of emotional-motivational and motor reactions.

[Tyrosine hydroxylase activity in the brains of rats with different levels of initial alcoholic motivation]. / Tirozingidroksilaznaia aktivnost' v mozge krys s razlichnymi urovniami iznachal'noi alkogol'noi motivatsii.

Activity and KM of hypothalamic tyrosine hydroxylase (TH) were studied in rats preliminarily tested for predisposition to high ethanol consumption. It was shown that as regards cofactor of DMPH4 enzymatic reaction, KM of hypothalamic TH of animals with an initially high alcoholic motivation is lower than that from the brain of animals rejecting alcohol, being 0.34 +/- 0.3 mM and 0.46+/- 0.10 mM, respectively. A conclusion is made that the catecholaminergic system is involved into the realization of the rewarding effects of ethanol.

[Effect of indomethacin and nonachlazine on myocardial and cerebral tyrosine hydroxylase activity in rats]. / Vliianie indometatsina i nonakhlazina na aktivnost' tirozingidroksilazy v miokarde i golovnom mozge krys.

Nonachlazin (6 mg/kg) and indomethacin (10 mg/kg) intraperitoneally have a unidirectional effect on the activity of tyrosin hydroxylase, reducing it in the hypothalamus and in the brain stem and increasing it in the heart septum. In the brain, the effects of nonachlazin and indomethacin are not summarized whereas in the heart their effects are summarized. Unlike indomethacin, nonachlazin exerts a direct effect on the rate of tyrosin hydroxylase reaction but has no effect on the activity of cyclooxygenase and on synthetase of prostaglandins. It is concluded that prostaglandins produce a modulating action on the activity of brain and heart tyrosine hydroxylase and participate in the mechanism of action of nonachlazin.

[Effect of chronic stress on the behavior, bodily condition, and cerebral tyrosine hydroxylase activity of "emotional" and "unemotional" rats]. / Vliianie khronicheskogo stressa na povedenie, somaticheskoe sostoianie i aktivnost' tirozingidroksilazy mozga "émotsional'nykh" i "neémotsional'nykh" krys.

The relationship between behavior manifestations, somatic alterations and brain tyrosine hydroxylase activity was studied in "emotional" and in "non-emotional" rats exposed to chronic stress. The drastic increase in tyrosine hydroxylase activity in the hypothalamus and striatum after stress correlates with disturbances in behavior, somatic defects (ulcers, erosions) in "emotional" rats as compared with "non-emotional" ones.