[Some features of enkephalin metabolism in the rat brain after administration of bestatin]. / Nekotorye pokazateli metabolizma énkefalinov v golovnom mozge krysy posle vvedeniia bestatina.

The effect of a single bestatin dose on enkephalin content, activities of enkephalin convertase, enkephalinase A and aminopeptidases as well as on the level of specific binding of (3H) (D-Ala-2,D-Leu-5)enkephalin in rat midbrain (including hypothalamus) and striatum has been studied. Using ANOVA and correlation analyses, the relationship between the changes in these parameters has been established. The different responses of the enkephalin system of rat brain seem to be due not only to differences in the ratios of the "enkephalinase" and "aminopeptidase" pathways of enkephalin catabolism but, also, to structural peculiarities of enkephalin-containing conduction tracts.

[The effect of naloxone on the activation, inducible by chronic alcoholic intoxication, of the membrane-bound form of enkephalin convertase in the midbrain and hypothalamus of rats]. / Vliianie naloksona na indutsiruemuiu khronicheskoi alkogol'noi intoksikatsiei aktivatsiiu membranno-sviazannoi formy énkefalinkonvertazy v srednem mozge i gipotalamuse krys.

The activity of membrane-bound and soluble enkephalin convertase was determined with dansyl-Phe-Leu-Arg as substrate in midbrain, including hypothalamus, of Wistar rats, who were given ethanol (20% solution i.g., 9-15 g/kg per day during 4 days) or naloxone (2 mg/kg i.p. twice a day during 4 days) or their combination. It was shown that activation of membrane-bound enzyme, observed after alcohol treatment of rats, didn't develop by combined ethanol-naloxone administration. It's supposed that alcohol-stimulating effect on this enzyme realizes throughout the hyperstimulation of opioid receptors by enkephalins and, possible, by other opioid-active compounds.

[The effect of the aminopeptidase inhibitor bestatin on the enkephalin level in the rat brain]. / Vliianie ingibitora aminopeptidaz bestatina na uroven' énkefalinov v mozge krys.

Met- and leu-enkephalin contents in midbrain (including hypothalamus) and striatum of rats were determined by radioimmunoassay after bestatin (racemate) injection (200 g, i.c.v.). It was found that bestatin administration influenced the midbrain met-enkephalin content, values and directions of the changes observed being dependent upon the time after the injection. The data obtained confirm the participation of aminopeptidase in enkephalin inactivation and present evidence for the possibility of regional variations of enkephalin catabolism pathways in the brain.

[Role of aminopeptidases in enkephalin catabolism: comparative study of the regional distribution of aminopeptidases and enkephalinase A in the rat brain]. / K voprosu o roli aminopeptidaz v katabolizme énkefalinov: sravnitel'noe issledovanie regional'nogo raspredeleniia aminopeptidaz i énkefalinazy A v golovnom mozge krysy.

In order to elucidate the role of aminopeptidases in enkephalin catabolism in rat brain, the local distribution of two types of cerebral cellular membrane aminopeptidases (puromycin-sensitive and puromycin-insensitive ones) and of the enkephalin system marker, enkephalinase A, was studied. It was found that the distribution patterns of the former enzymes differ essentially from that of enkephalinase A. Study of coupling between the enzymatic activities in different regions of rat brain revealed a strong correlation between the activities of puromycin-insensitive aminopeptidase and enkephalinase A in midbrain (including hypothalamus). It was supposed that in midbrain the role of aminopeptidase M in intrasynaptic inactivation of enkephalins is much more conspicuous than in other regions of rat brain. The puromycin-sensitive aminopeptidase activity does not seem to play a role in enkephalin catabolism.

[Dynamics of met-enkephalin level in the adrenal glands and plasma of rats during acute alcoholic intoxication]. / Dinamika soderzhaniia met-énkefalina v nadpochechnikakh i plazme krovi krys pri ostroi alkogol'noi intoksikatsii.

Content of Met-enkephalin in rat adrenal glands and blood plasma as well as activity of the enzymatic systems catalyzing the enkephalins catabolism in blood serum were studied after a single administration of ethanol into rats. Dynamics of Met-enkephalin alterations studied suggest that phases of activation and inhibition occur in the secretion of the peptide from adrenal gland into circulation.

[Enkephalin convertase activity in various brain regions of rats during alcoholic intoxication]. / Aktivnost' énkefalinkonvertazy v otdelakh mozga krys pri alkogol'noi intoksikatsii.

Effects of single and chronic administrations of ethanol into rats on activity of soluble and membrane-bound forms of enkephalin convertase were studied in various parts of brain. Regional alterations in the patterns studied dependent on duration of alcoholization were observed. Enkephalin convertase appears to be involved in development of tolerance to alcohol.

[Effect of diazepam on the specific binding of 3H-(D-Ala-2, D-Leu-5)-enkephalin by striatal membranes in the rat]. / Vliianie diazepama na spetsificheskoe sviazyvanie 3H-(D-Ala-2, D-Leu-5)-énkefalina membranami striatuma krys.

The effect of a single intraperitoneal administration of diazepam (relanium) (2.5 mg/kg) on specific binding of 3H-(D-Ala-2, D-Leu-5)-enkephalin (10 nM) by the rat striatum membranes was studied. The drug was shown to increase the binding activity of opioid receptors 15 minutes after the injection. At prolongation of the animal exposure by up to 45 minutes the magnitude of the activity decreases below the control level. Under in vitro conditions diazepam shows the activating effect which is similar to that ex vivo. It was found that the changes in the opioid receptor binding activity were produced by alterations of the maximal number of specific binding sites.

[Effect of ethanol on the enkephalinergic opioid system of the rat brain]. / Vliianie étanola na énkefalinergicheskuiu opioidnuiu sistemu mozga krys.

The effects of ethanol were examined on the main parameters of rat brain enkephalinergic neurotransmission, e.g., enkephalinase A activity, enkephalin content and specific binding of 3H-morphine and 3H-(D-Ala2, D-Leu5)-enkephalin. Administration of ethanol in a single dose led to significant changes in the tested parameters; upon chronic treatment with ethanol these changes were either less pronounced or altogether absent. The stimulating effect of ethanol on the release and utilization of enkephalins was supposed. Evidence in favour of the hypothesis on the functional relationship between the opiate receptors of the delta-type and enkephalinergic neurotransmission was obtained.

[Mechanism of action of ethanol on enkephalinase A activity in the rat brain]. / Issledovanoe mekhanizma deistviia étanola na aktivnost' énkefalinazy A mozga krys.

The influence of ethanol, its metabolites and some opiates on enkephalinase A activity was studied in rat experiments in vitro after acute and chronic administration of ethanol. It was demonstrated that addition of ethanol to the reaction mixture activated enkephalinase A of the midbrain and hypothalamus of intact rats, the maximal effect being attained at an ethanol concentration of 10(-3) M. Multiple washings with buffer of the ethanol-preincubated membranous fraction of these brain structures in the control rats did not lead to a significant reduction in the activating effect of ethanol on enkephalinase A. No activation was recorded upon the use of an enzymatic preparation of the brain from chronically alcoholized animals. Morphine, naltrexon, beta-carbolines, salsolinol (10(-4) M) and acetaldehyde (10(-8)-10(-2) M) did not activate the enzyme. It is suggested that enkephalinase A activation in rats given ethanol is determined by a direct action of ethanol on the enzyme.

[Effect of chronic alcohol consumption on activity of enkephalinase A in rat striatum, hypothalamus and midbrain]. / Vliianie khronicheskogo potrebleniia alkogolia na aktivnost' éntsefalinazy A v striatume, gipotalamuse i srednem mozge krys.

A modified procedure is developed for estimation of encephalinase A activity in rough membrane material from rat brain; the accuracy of the procedure was about +/- 5% and sensitivity--0.2 X 10(-15)M of 3H-Tyr-Gly-Gly per min if labelled Leu-encephalin was used as a substrate. Activity of encephalinase A in midbrain and hypothalamus was increased by 10% and in striatum--by 25% after chronic consumption of alcohol within 6 weeks. Rates of specific binding of 3H-Leu-encephalin with opiate receptors in the brain departments studied of the alcohol-treated rats were similar to those of control values. Encephalinase A appears to participate in development of dependence on alcohol or tolerance to it.

[Proteins of bacterial membranes. H+-adenosinetriphosphatase from Acholeplasma laidlawii cells]. / Belki bakterial'nykh membran. H+-adenozintrifosfataza kletok Acholeplasma laidlawii.

The cytoplasmic membrane of micoplasmic cells, in particular of A. laidlawii cells, contains a proton-carrier Mg2+ -activated ATPase. A whole H+ -ATPase complex (F0-F1) was isolated from these cells and characterized. The isolation procedure included solubilization of the enzyme with Triton X-100 followed by ion-exchange chromatography on DEAE-cellulose and gel filtration on Sepharose 6B. The enzyme was inhibited by dicyclohexylcarbodiimide (10(-4) M). The Km value for ATP hydrolysis and Ki for ADP hydrolysis were determined. The order of the constants did not differ from those measured earlier for factor F1 of the complex. The purified enzyme, similar to its hydrophylic moiety is sensitive to the action of bivalent cations. The subunit composition of the whole complex and of its water-soluble part was investigated. The complex was found to contain 11 polypeptides, five of which belong to factor F1. The molecular weights of these polypeptides were determined.