Effect of 3-substituted 1,4-benzodiazepin-2-ones on bradykinin-induced smooth muscle contraction.

Biochemical properties of 3-substituted 1,4-benzodiazepine determined by the characteristics of their chemical structure. Influence of 3-substituted 1,4-benzodiazepin-2-ones on maximal normalized rate and amplitudes of isometric smooth muscle contraction in rats was investigated. Compounds MX-1775 and MX-1828 demonstrated the similar inhibition effect on bradykinin-induced contraction of smooth muscle like competitive inhibitor des-arg9-bradykinin-acetate to bradykinin B2-receptors. MX-1626 demonstrated unidirectional changes of maximal normalized rate and force of smooth muscle that proportionally depended on bradykinin concentration in the range 10-10-10-6 M. MX-1828 has statistically significant decrease of normalized rate of smooth muscle contraction for bradykinin concentrations 10-10 and 10-9 M by 20.7 and 8.6%, respectively, but for agonist concentration 10-6 M, this parameter increased by 10.7% and amplitude was reduced by 29.5%. Compounds MX-2011, MX-1785 and MX-2004 showed no natural effect on bradykinin-induced smooth muscle contraction. Compounds MX-1775, MX-1828, MX-1626 were selected for further research of their influence on kinin-kallikrein system and pain perception.

Dose-dependent IFN-stimulating and immunomodulating properties of 6H-indolo[2,3-B] quinoxaline derivatives.

Two 6H-indoloquinoxaline derivatives were studied in different doses and schemes of application for their INFgamma-inducing potential and ability to effect functional activity of phagocytic cells. Tested compounds were shown to possess comparable or higher activity than reference drug Amixin in analogous doses. One indoloquinoxaline significantly elevated metabolic activity of macrophages and increased their potential for phagocytosis. Application of multiple treatments and higher doses allowed us to reveal differences between studied derivatives that were not obvious in previous in vivo experiment. Capacity of 6H-indoloquinoxalines to induce vast IFN amounts on in vivo level was demonstrated for the first time.

[Effects of amixine on electrophoretic mobility of murine T lymphocytes].

The amixine-induced early changes in the electrophoretic mobility (EPM) of murine splenic T lymphocytes were studied in vitro by the microelectrophoresis technique. It has been found that T lymphocytes treated with amixine have a greater EPM within the first hours of amixine addition than control cells. This change in EPM depends on the concentration of amixine in the medium and the duration ofamixine exposure. It was concluded that the amixine-treated cells have a greater net negative surface charge density than control cells. This effect may play an important role in the cell-cell interaction during the immune response.

Elevation of efficacy of cancer vaccine combined with interferon and inducer of endogeneous interferon synthesis amixin.

AIM: To study in vivo efficacy of combined administration of cancer vaccine (CV), interferon (IFN) and inducer of endogenous IFN - amixin. MATERIALS AND METHODS: Sarcoma-37 cells were transplanted to female Balb/c mice. For the treatment, CV prepared from sarcoma-37 cells with the use of cytotoxic lectines from B. subtilis B-7025, murine IFN and amixin or their combinations were used. IFN production, content of circulating immune complexes and level of specific IgG antibodies in blood serum were determined by standard immunologic methods. RESULTS: Using solid form of sarcoma-37 it has been shown that introduction of IFN and amixin significantly elevated efficacy of vaccine therapy, in particular index of tumor growth inhibition reach 89.2% and 81.7%. Upon combined use of CV and IFN or CV and amixin (25 mg/kg) respectively. Significant prolongation of average life span of the animals treated with CV and IFN or CV and amixin (25 mg/kg) has been registered (up to 92.7 -/+ 10.4 and 95.0 -/+ 6.2 days respectively, vs 46.8 -/+ 1.5 days for control animals). CONCLUSION: Obtained results have shown expediency of the development of schemes for combined introduction of CV with exogenous IFN, and with inducer of endogenous IFN (amixin) for elevation of efficacy of vaccine therapy.

Quantitative structure-affinity relationship of 5-HT1A receptor ligands by the classification tree method.

The influence of molecular structure of 346 ligands on their affinity for 5-HT1A receptors was investigated. It was shown that the effectiveness of the proposed novel approach for interpretation of decision tree models compared favourably with the PLS method. In the context of the proposed approach, molecular fragments and their values of the relative influence on the affinity for 5-HT1A receptors were defined.

[Interferonogenic activity of amixin analogs and diphenyl derivatives].

Properties of interferon productivity of several inducers of interferon, analogs of amixin, have been studied in vivo. It has been shown, that under the influence of injected agents the content of endogenic interferon in the blood serum of laboratory animals increased and their non-fractionated cells of the peripheral blood (splenocites and macrophages) synthesized alpha- and gamma-interferon.

Peptidomimetics - antagonists of the fibrinogen receptors: molecular design, structures, properties and therapeutic applications.

The platelet aggregation is a crucial step in a pathophisiology of thromboses, leading to development of cardio-vascular diseases (myocardial infarction, transient ischemic attacks, strokes, etc.). The final step in the aggregation is the binding of fibrinogen to receptor - glycoprotein IIb/IIIa (GP IIb/IIIa) on the surface of activated platelets. In recent years the increasing attention is paid to the role of fibrinogen antagonists in the prevention of thrombosis. The search for these compounds is based on the molecular design of structures mimicking some fragment of RGD (Arg-Gly-Asp) sequence, responsible for the binding of fibrinogen to GP IIb/IIIa. Up to now, a large number of potent and selective GP IIb/IIIa antagonists, including non-peptide inhibitors are identified (derivatives of benzodiazepines, aminobenzamidinosuccinyles, isoxazolines, isoquinolines). The modification of natural peptide structures for obtaining of more active and selective fibrinogen receptor antagonists is realized in several ways: substitution of main pharmacophores of RGD sequence; cyclization of RGD-containing peptides; design of conformationally constrained peptidomimetics. For the treatment of chronic cardio-vascular diseases, the clinic needs high orally active RGD-peptidomimetics. This task is realized by obtaining of prodrugs on the base of the most potent RGD-mimetics. In our laboratory the molecular design and synthesis of non-peptide fibrinogen receptor antagonists were carried out. The series of RGD-mimetics on the basis of 4-oxo-(piperazine-1-yl)butyric acid as Arg-mimetic and beta-aryl-beta-alanines as Asp-Phe-mimetics were synthesized. Obtained RGD-mimetics showed a high antiaggregatory activity in vitro experiments with IC(50)values of 10(-7) - 10(-9) M.

Affinities of gidazepam and its analogs for mitochondrial benzodiazepine receptors.

Mitochondrial benzodiazepine receptors (MBRs) participate in many physiological processes, such as calcium flow regulation, proliferative and respiratory cell functions, mitochondrial steroidogenesis and adaptational reactions to stress. We have found that the selective anxiolytic gidazepam has a higher affinity for CNS MBRs as compared to central benzodiazepine receptors. The ability of gidazepam to bind to MBRs probably underlies a wide spectrum of its pharmacological effects. We have studied affinities of gidazepam analogs for CNS MBRs in search for the ligands possessing higher affinity and selectivity. The experiments were carried out with male Wistar rats weighing between 200-220 g. Affinities of the investigated compounds were assessed on their ability to displace radioligand Ro5-4864 from its specific binding sites on MBRs of rat brain. Within the series of tested compounds three substances comparable on affinity with Ro5-4864 were found. Experimental results have shown that the presence of chlorine atom in o-position of 5-phenyl substituent leads to a 10 to 15-fold increase in affinity for CNS MBRs. We have also found that the essential contribution in affinity of the investigated series is brought by lipophilicity of substituent in IN-position. Our data may be useful in design and synthesis of novel potent selectively acting ligands of CNS MBRs.

[Biochemical mechanisms of realization of antiviral and interferon-inducing activity of amixine and its analogs]. / Biokhimicheskie mekhanizmy realizatsii protivovirusnoi i interferonindutsiruiushchei aktivnosti amiksina i ego analogov.

Antiviral and interferon inducing activity of the amixine and its some derivatives, as well as their influence on the proteolytic enzymes activity, monooxygenase activity of the microsomal fraction, level of the lipids peroxidation were studied. Lack of correlation between antiviral and interferon inducing activity in the investigated series of compounds was found. Vice versa, the good correlation between interferon inducing activity and the elastase-like activities inhibition ability of the compounds was observed. It allows to state the assumption, that only one ability of compounds to induce of an interferon doesn't suffice for obtaining of high titres of interferon, and while their rather high antiproteolitic activity is necessary. It's shown, that except for one compound the influence of amixine and its derivatives on the red-ox enzymes activity well correlates with their ability to the interferon-inducing. All presented above allows to attribute amixine and its derivatives to polymodal antiviral agents.

Biological active acridine derivatives. Part 4: Synthesis and antiviral activity of some bis-acridinylated diamides.

Nine bis-acridine derivatives have been synthesized in search of structures with antiviral properties. Synthesis of target compounds was provided by a standard peptide-like coupling procedure using aliphatic diamines and protected amino acids following protective group removing and acridinylation by means of 9-methoxyacridine. Two out of nine compounds tested demonstrate high protective activity of Vero cells against HSV infection. Antiviral activity was observed only for compounds containing a pentamethylene fragment as a linker. The alanyl-containing derivative was less active than those containing valyl- and phenylalanyl. Most of synthesized compounds were less toxic than N,N'-bis-(acridinyl) hexamethylenediamine.

Biokinetics of transdermal therapeutic medicinal form of phenazepam.

We studied the rate of phenazepam absorption into the blood and its transport to the brain from a transdermal therapeutic system and bioavailability of the drug in this system. Hydrogel matrix consisting of polyvinyl alcohol and 1,2-propylene glycol was used for application. Transdermal application of 0.1-0.4 mg phenazepam in a dose of 14 mg/kg provided a stable level of this drug during application interval (1-48 h), while its bioavailability for blood plasma and brain was 0.63 and 0.2, respectively (determined for 0.4 mg phenazepam). The rate of drug penetration into the blood and brain was 46 and 60 ng/ml/h, respectively.

Synthesis and properties of peptidomimetics--inhibitors of platelet aggregation.

The literature data on effective approaches to the development of the novel peptidomimetics, antagonists of fibrinogen GP IIb/IIIa receptors as potential antithrombotic agents are generalized and systematized in the review. The data obtained by the authors on the synthesis and properties of novel peptidomimetics are reported.

TRH mimetics: differentiation of antiamnesic potency from antidepressant effect.

For the purpose of rational modification of the TRH molecule, we were pursuing an approach that consists of two steps: (1) 'obligatory' replacement of histidine with glutamine in TRH and (2) the application of conformational constraints for putative bioactive conformation I stabilized by an intramolecular hydrogen bond between C-terminal carboxamide proton and alpha-carbonyl of histidyl (glutaminyl), and conformation II formed by an intramolecular hydrogen bond between alpha-carbonyl of pyroglutamyl and prolinamide proton. Significant antiamnesic potency was discovered in the passive avoidance test (ECS and Scopolamine induced amnesia) for conformation II mimic (8S,10aS)-8-carbamoyl-1,2,3,6,7,8,9,10a- octahydro-5H,10H-pyrrolo[1,2-a][1,4]diazocin-5,10-dione (2) at doses of 0.1 and 1.0 mg/kg. EEG analysis indicates a mild activating effect of compound 2 on EEG, which is similar to that of piracetam and differs from hard amphetamine activation. Conformation I mimic 3-(2-carbamoylethyl)-2,3,6,7,8,8a-hexahydro-1H,4H-pyrrolo[1,2-a] pyrazin-1,4-dione (1) exhibited an antidepressant effect at a dose of 1 mg/kg. The transition from two putative quasi-cyclic bioactive conformations of TRH and its obligatory similar analogue [Gln2]-TRH to their cyclic mimics led to differentiation of antiamnesic and antidepressant activity of TRH.

[An amplitude-interval analysis of the electrocorticogram of the normal rat and under the action of fenamine and buspirone]. / Amplitudno-interval'nyi analiz élektrokortikogrammy krysy v norme i pri deistvii fenamina i buspirona.

The ECoG effects of natural vigilance changes were analysed on a microcomputer in rats. In addition, the effects of the psychostimulant phenamine (1 mg/kg, i.p.) and the anxiolytic buspirone (1.5 mg/kg, i.p.) were studied. The ECoG data were processed using the amplitude-interval analysis technique. The two drugs significantly modified ECoG: the maximum effect was observed within the first 30 min after buspirone administration and at 30-60 min after phenamine. Each drug affected the ECoG in its own particular manner, which was similar to their natural activation, but not identical to it. The findings provide evidence for the assumption that the activation processes play an important role in making buspirone show its psychotropic effects.

Stabilization of the peptide conformation on the micellar surface.

The conformational mobility of peptide molecules plays a significant role in peptide-receptor interactions and quantitative structure-activity relationships. As a receptor mimetic system, bis(2-ethylhexyl) sodium succinate (AOT) reversed micelles containing an aqueous solution of one of the melanotrophine inhibiting factor analogues prolyltyrosyl-glycinamide hydrochloride in the inner cavity have been used. Two-dimensional nuclear magnetic resonance spectroscopy (NOESY) and 13C spin-lattice relaxation time measurements have been used to establish that the peptide molecule assumes the biologically active beta II turn conformation when it is adsorbed at the surfactant-water border. This conformation is stabilized by intramolecular H-bonding between the proline carbonyl oxygen atom and amide protons. Moreover, it has been shown that the phenyl ring of tyrosine was inserted into the AOT intermolecular cavity, which is located between the polar AOT groups and the branches of iso-octane fragments. By and large, the phenyl ring acts as a hydrophobic anchor. Reversed micelles can be regarded as providing a realistic model of the receptor.

Formation of pyroglutamylglutamine (or asparagine) diketopiperazine in 'non-classical' conditions: a side reaction in peptide synthesis.

Formation of by-products pyroglutamylglutamine diketopiperazine (5a) or pyroglutamylasparagine diketopiperazine (5b) were observed during the condensation of pyroglutamic acid active ester with C-protected glutaminyl(or asparaginyl)-proline derivatives. Successful synthesis of Glp-Gln(or Asn)-Pro-derivatives is possible after coupling of Glp-Gln(or Asn)-OH with proline-derivatives.