Antiplatelet and Antithrombotic Properties of Compound L-36, a 6H-1,3,4-Thiadiazine Derivative.

Compound L-36, a new derivative of 6H-1,3,4-thiadiazine, was studied in in vitro and in vivo experiments. This compound exhibits high antiplatelet and antithrombogenic activity. In in vitro experiments, compound L-36 by its antiplatelet activity (by IC50) was superior to acetylsalicylic acid by 9.4 times. In in vivo experiments, compound L-36 by its ED50 value was close to the comparison drug. On the model of pulmonary artery thrombosis, compound L-36 ensured better survival of experimental animals than acetylsalicylic acid. Morphological studies showed that compound L-36 effectively attenuated the thrombosis processes in the pulmonary tissue induced by intravenous injection of a thrombogenic mixture (epinephrine and collagen).

Antiplatelet Activity of Riamilovir under Conditions of Lipopolysaccharide Intoxication.

We studied the effect of antiviral agent riamilovir on ADP-induced platelet aggregation in the absence and presence of LPS. Unlike acetylsalicylic acid (reference drug), riamilovir did not exhibit antiplatelet effect in vitro. However, it markedly suppressed platelet reactivity in LPS-treated blood samples and was 2.2-fold superior to acetylsalicylic acid in terms of IC50 value. In in vivo experiments, riamilovir under conditions of hypercytokinemia blocked platelet aggregation in rats by 64%.

Antithrombotic Activity of the Antiplatelet Agent Angipur on the Model of Arterial Thrombosis in Rats with Isoproterenol-Induced Myocardial Infarction.

We studied the effect of Angipur on the process of experimental thrombosis induced by damage to the carotid artery wall by surface application of 50% ferric chloride (III) solution in rats without comorbidities and with isoproterenol-induced myocardial infarction. In animals without comorbidities, Angipur administered intravenously was 1.2 times less effective, in terms of ED50, than the well-known inhibitor of GPIIb/IIIa platelet receptors tirofiban. However, under conditions of non-coronary myocardial infarction, Angipur significantly prolonged the time of thrombus formation and exhibited 1.4-fold higher activity than the reference drug tirofiban.

Effects of Zoniporide and BMA-1321 Compound on the Rate of Oxygen Absorption by Cardiomyocyte Mitochondria in Rats with Experimental Chronic Heart Failure.

Uncoupling of respiration and ATP production by myocardial mitochondria was observed in rats with chronic isoproterenol intoxication (L-isoproterenol subcutaneously, 1 mg/kg, for 10 days) in comparison with controls (injected with the solvent). Inhibitors of NHE-1 zoniporide (1 mg/kg intraperitoneally, 13 days) and BMA-1321 compound (0.92 mg/kg intraperitoneally, 13 days) improved the mitochondrial function in rats with isoproterenol-induced cardiac failure: respiratory control coefficients increased, more so for the respiratory chain complex II, the main source of ROS in heart failure. The effect of BMA-1321 was more manifest (53%; p<0.05) in comparison with zoniporide (35%; p<0.05).

Antithrombotic Activity of a Novel Diazepino[1,2-α] Benzimidazole Derivative on Arterial Thrombosis Model in Rats without Concomitant Pathology and in Rats with Experimental Myocardial Infarction.

Antithrombotic activity of a novel tricyclic derivative of diazepino[1,2-α]benzimidazole (DAB-15) was examined on the model of arterial thrombosis developed in rats without concomitant pathology and in rats with experimental myocardial infarction. DAB-15 demonstrated high antithrombotic efficacy in modeled thrombosis of carotid artery in rats without the concomitant pathology surpassing that of the reference drugs acetylsalicylic acid and clopidogrel by 5.1 and 4.8 times, respectively. In rats with experimental noncoronary myocardial infarction, DAB-15 increased the thrombus formation time by 86.2% in comparison with experimental control level in non-treated rats with similar myocardial infarction.

GABAergic Mechanism of Anticonvulsive Effect of Chemical Agent RU-1205.

The study examined the effect of 9-(2-morpholinoethyl)-2-(4-fluorophenyl)imidazo[1,2-α] benzimidazole dihydrochloride (RU-1205) on the latency of seizures provoked by corazol, bicuculline, or picrotoxin. This agent (10 and 20 mg/kg) increased the seizure latency in the experimental models of epileptogenesis. The blockers of GABAA and GABA A -ρ receptors picrotoxin and (1,2,5,6-tetrahydropyridin-4-yl)methylphosphinic acid, respectively, were employed to study the effects of RU-1205 on electrical activity of somatosensory cortical neurons and on formation of pathological rhythms in the rat brain. RU-1205 inhibited the focal background rhythm and eliminated the epileptiform activity, which can be mediated by interaction with GABAA receptors.

Effect of GRP119 Receptor Agonist, Compound MBX-2982, on Activity of Human Glucokinase.

Validation of the method for studies of glucokinase activators by the spectrophotometric method in an in vitro test system is carried out. The advantage of NAD coenzyme vs. thio-NAD is proven. Manifest activation of glucokinase by MBX-2982 compound (GPR119 agonist) in a wide range of concentrations is demonstrated experimentally.

Effect of Compound Sbt-828, a New Indole Derivative Exhibiting Antiaggregant Activity, on the Prostacyclin-Thromboxane A2 Balance.

We investigated the effect of a new indole derivative Sbt-828 with antiaggregant properties on prostacyclin-generating activity of the vascular wall and thromboxane A2 level in platelets of intact rats. The substance under study did not affect prostacyclin production by the vascular wall and significantly reduced thromboxane A2 level, being superior to the reference drug acetylsalicylic acid by 1.6 times, as seen from reduced malonic dialdehyde level in the thrombin-induced rat platelets.

Study of µ- and δ-Opioid Activities in Agents with Various κ-Receptor Selectivity.

A putative opioid agonist RU-1205 was ineffective within in vitro model of electrically induced contractions of rat ileum assessing the µ- and δ-opioid receptor pathways, while morphine inhibited these contractions in a dose-dependent and naloxone-reversible manners with EC50=2.6×10-7 M. In vivo experiments revealed no significant effects of RU-1205 on respiration and gastrointestinal tract contractile activity. In contrast, butorphanol decreased respiration rate by 25% (25-100 mg/kg) and slowed down the transit of labeled particles along the small intestine by 77.1% (1 mg/kg) and by 45.5% (10 mg/kg). Morphine-induced inhibition of peristalsis was dose-dependent with maximum effect (by 68.6%) observed in the dose of 10 mg/kg. It was concluded that the effects of RU-1205 are not related to activation µ- and δ-opioid receptors known to mediate the effects of non-selective opioid agonist morphine and agonist-antagonist butorphanol.

Antithrombotic Activity of DAB-15, a Novel Diazepinobenzimidazole Compound.

Antithrombotic activity of a new orally administered antiplatelet compound DAB-15 was compared to that of acetylsalicylic acid, ticlopidine, and clopidogrel in the experimental model of arterial thrombosis in rats caused by surface application of 50% ferric chloride (III) on the carotid artery. Compound DAB-15 exerted a dose-dependent antithrombotic effect and was superior to acetylsalicylic acid, ticlopidine and clopidogrel by 5, 7, and 4.9 times, respectively (by ED50). This necessitates studying of the action mechanism of this antiplatelet compound with consideration of its influence on different stages of the pathogenesis of platelet aggregation.

Effect of a New Antioxidant Enoxifol on Platelet Aggregation and Blood Rheological Properties in Rats with Experimental Diabetes Mellitus.

Effect of a new antioxidant enoxifol exhibiting antiplatelet activity in vitro and in vivo on hemostasis parameters was assessed in laboratory rats with experimental diabetes mellitus. Gliclazide, a hypoglycemic agent with antiplatelet properties, and pentoxifylline, a preparation improving blood rheology, were used as the reference drugs. Enoxifol produced a pronounced inhibitory effect on platelet aggregation in rats with experimental diabetes comparable to the effect of gliclazide and decreased blood viscosity thus demonstrating a significant effect comparable to that of pentoxifylline. In view of the fact that oxidative stress is a pathogenetic components of vascular complications in diabetes, it can be assumed that improvement of hemostasis parameters under the effect of enoxifol is determined by its antiplatelet and antioxidant activities.

Antiepileptic Activity of a New Derivative of Benzimidazole RU-1205.

Antiepileptic activity of a new derivative of benzimidazole RU-1205 was studied on the model of pentylenetetrazole-induced generalized seizures in mice. Sodium valproate was used as the reference substance. RU-1205 was superior to sodium valproate by anticonvulsant activity (by 12 times) and therapeutic index (by 8.5 times). In contrast to sodium valproate, RU-1205 exhibited significant anticonvulsant activity on the model of pentylenetetrazole-induced kindling without tendency to resistance development.

[COMPARATIVE STUDY OF THE INFLUENCE OF BENZIMIDAZOLE DERIVATIVE RU-1205, DIAZEPAM, AND SODIUM VALPROATE ON THE SEIZURE THRESHOLD, ANTICONVULSANT TOLERANCE, AND REBOUND EFFECTS.]

We have studied the effects of acute administration of benzimidazole derivative RU-1205 (9-(2-morpholinoethyl)-2-(4-fluorophenyl)imidazo(1,2-alpha)benzi- midazole), diazepam, and sodium valproate on the threshold for myoclonic and clonic seizures in response to i.v. infusion of pentylenetetrazole (PTZ) in mice. Furthermore, the effects of chronic administrations of RU-1205 and diazepam on the development of anticonvulsant tolerance and rebound phenomena were evaluated. The TID50 values (the dose of anticonvulsant required to increase the PTZ seizure threshold by 50%) of RU-1205, diazepam, and valproate for my- oclonic seizures were 7.9, 120.4, and 1.2 mg/kg (i.p.), respectively. TID50 of RU-1205, diazepam, and valproate for clonic seizures were 7.9, 116.9, and 1.3 mg/kg (i.p.), respectively The chronic administration of RU-1205 (31 mg/kg, i.p., 28 days) did not lead to the development of anticonvulsant tolerance or rebound effect after discontinuation of treatment. The anticonvulsant effect of diazepam (5 mg/kg, i.p., 28 days) in chronically treated mice was gradually abo- lished and the rebound effect was observed after the discontinuation of treatment.

STUDYING THE PHYSICAL DEPENDENCE ON AND TOLERANCE TO THE ANTINOCICEPTIVE EFFECT OF RU-1205 SUBSTANCE.

We have studied the physical dependence on and tolerance to the analgesic activity of compound RU-1205. It is established that this compound does not cause side effects typical of morphine and butorphanol including the development of withdrawal syndrome upon naloxone provocation and tolerance to analgesic activity upon 14-day administration.

[ANTIAGGREGANT ACTIVITY OF A NEW TRICYCLIC BENZIMIDAZOLE DERIVATIVE.]

The antiaggregant activity of a new benzimidazole derivative - 2,3,4,5-tetrahydro[1,3]diazepino[1,2-α]benzimidazole (DAB-15) has been investigated in vitro in comparison to reference drugs acetylsalicylic acid (ASA) and ticlid (ticlopidine) on the models of ASA, collagen, and epinephrine induced platelet aggregation in rabbits. It was established that DAB-15 exhibited dose-dependent antiaggregant activity. On the model of ASA-induced platelet aggregation, the effect of ADB-15 exceeded that of ASA and was slightly lower than that of ticlid. On the models of collagen, and epinephrine induced platelet aggregation, DAB-15 was reliably more active than the both reference drugs.

NEUROPROTECTIVE PROPERTIES OF A NEW INHIBITOR OF NA+/H+ EXCHANGER (COMPOUND RU-1355) ON THE MODEL OF FOCAL ISCHEMIA IN RATS.

Primary neuroprotective properties of new inhibitor of Na⁺/⁺ exchanger (compound RU-1355) were established on the model of 60-min focal ischemia of the left middle cerebral artery followed by 24-h reperfusion in rats. Compound RU-1355 significantly (by 34%) decreased neurological symptoms, reduced (1.67 times) the growth of neuron-specific enolase level in serum, decreased (2.3 times) the size of the necrotic zone, and reduced by 59% (p <0.05) the degree of cerebral edema According to the results of morphometric, immunoassay, and neurological assessments of brain damage, compound RU-1355 is superior on ave- rage by 43.5% (p < 0.05) in comparison to selective NHE1 inhibitor zoniporide.

Antithrombotic Activity of a New Hypoglycemic Compound Limiglidole in Mouse Model of Cell Thrombosis.

Antithrombotic activity of hypoglycemic compound limiglidole that exhibits antiplatelet activity 2-fold exceeded activity of antiplatelet agent acetylsalicylic acid in the mouse model of systemic collagen-epinephrine thrombosis. Limiglidole signifi cantly reduced the relative and mean area of blood clots in the sections of mouse lungs.

Effect of Pyrrolobenzimidazole Derivative RU-792 on Experimental Brain Ischemia.

Compound RU-792 showed pronounced anti-ischemic activity and improved survival of rats with brain ischemia by normalizing parameters of spontaneous motor activity and reducing neurological deficit within 3 post-operative days being superior to the reference drug mexidol by this parameter. RU-792 inhibited the formation of conjugated dienes and malonic dialdehyde and increased activity of the antioxidant enzyme glutathione peroxidase thereby modulating the parameters of free radical oxidation in rats subjected to ischemia more effectively than mexidol.

Antithrombotic activity of a new benzimidazole derivative in the thrombosis model in mice.

Antithrombotic activity of a new benzimidazole derivative RU-891, characterized by antiaggregant activity, vs. reference drug acetylsalicylic acid was studied on the epinephrinecollagen thrombosis model in mice. Antithrombotic activity of RU-891 3-fold surpassed that of the reference drug. Histological studies showed that RU-891 significantly reduced the relative and mean areas of thrombi in sections of mouse lungs in comparison with the control.

In vitro method of studying the angiotensin activity of chemical compounds.

We developed and tested an experimental model to study in vitro the type 1 angiotensin antagonistic activity of compounds on the isolated portal vein of rats. The reliability of this method was confirmed in tests with saralasin (nonselective antagonist of angiotensin receptors) and losartan (selective antagonist of type 1 angiotensin receptors) in concentrations of 10(-9)-10(-5) mol/liter. The half-maximal inhibitory concentrations (IC50) of these substances were calculated.