[Experimental hemorrhagic stroke].

The authors propose the technique of experimental haemorrhagic stroke of a hypertensive type in non-narcotized rats produced by means of gravity overload in the caudocranial vector with the use of a special centrifuge.

[Effect of ketamine on cerebral circulation of intact and ischemic animals]. / Vliianie ketamina na mozgovoe krovoobrashchenie intaktnykh i ishemizirovannykh zhivotnykh.

The influence of ketamine on the local cerebral circulation was studied in intact rats and under the conditions of global brain ischemia. The drug increased the local blood flow in intact rats. Despite pronounced hypotension accompanying the global brain ischemia, ketamine helped maintenance of the cerebral circulation.

[Brain ischemia induced by gravitational overload]. / Ishemiia golovnogo mozga, vyzvannaia gravitatsionnoi peregruzkoi.

It is suggested that radial gravitational overloads in craniocaudal direction, during which the pressure in meningeal arteries drops to zero, can be used to model the ischemic state. The post-ischemic period is characterized by increasing content of lipid peroxidation products in the venous blood and by violation of the neurological state in rats. This ischemia model, requiring no anaesthesia for the experimental animals, can be used in the directed search for new neuroprotectors and their characterization.

[The anti-ischemic effects of 3-hydroxypyridine derivatives in cerebrovascular pathology]. / Protivoishemicheskie éffekty proizvodnykh 3-oksipiridina pri tserebrovaskuliarnoi patologii.

The effect of the antioxidant mexidol and two new derivatives of 3-oxypyridine, namely LBK-10 and LBK-39 on the circulation of blood and metabolism of the brain in the postischemic period was studied in acute experiments on narcotized cats under conditions of autohemoperfusion of the cerebral vessels with a stable volume of blood. Therapeutic injection of mexidol and LBK in a dose of 20 mg/kg inhibited the development of the no-flow phenomenon and restored the ischemia damaged metabolism in the brain tissues. LBK-10 reduced the lactate content in the blood flowing from the brain and contributed to constriction of the cerebral vessels.

[The action of emoxipin, lithium oxybutyrate and pikamilon on the blood circulation of the ischemic brain]. / Izuchenie deistviia émoksipina, litiia oksibutirata i pikamilona na krovoobrashchenie ishemizirovannogo mozga.

Acute experiments were conducted on rats under nembutal anesthesia to compare the efficacy of emoxipin with that of lithium oxybutyrate and picamilon in the postischemic period after preventive and therapeutic injections in various doses. Emoxipin proved to be most effective in prevention of postischemic non-restoration of the flow of blood in the brain and in preservation of the autoregulation responses of the cerebral vessels. The possible mechanisms of the effect of the drug are discussed.

[The effect of 3-hydroxypyridine derivatives on postischemic disorders in the autoregulatory reactions of the cerebral vessels]. / Vliianie proizvodnykh 3-oksipiridina na postishemicheskie narusheniia autoreguliatornykh reaktsii mozgovykh sosudov.

Acute experiments on nembutal anesthetized rats showed improvement of cerebral blood flow autoregulation in the postischemic period under the effect of mexidol and the new 3-hydroxypyridine (3-HOP) derivatives LBK-10 and LBK-38 administered for prophylactic and therapeutic, purposes. The role of dopaminergic activity, solubility in lipids, and other factors in the mechanism of the activity of 3-HOP derivatives is analysed.

[The effect of cytochrome c preparations on the autoregulation of the cerebral blood flow in ischemia]. / Vliianie preparatov tsitokhroma c na autoreguliatsiiu mozgovogo krovotoka v usloviiakh ishemii.

The effect of animal cytochrome C (Ca), biotechnological cytochrome (Cb) and its hemtetradecapeptide (HTDP) on cerebral blood flow autoregulation during rapid decrease of systemic arterial pressure (SAP) was studied in acute experiments on rats. Cytochrome C preparations caused no effect on the autoregulatory responses of the cerebral vessels in animals with normal cerebral circulation. Injection of 5 mg/kg Ca and Cb and 0.8 mg/kg HTDP promoted restoration of the phenomenon of cerebral blood flow autoregulation in ischemic brain damage in change of SAP from 120 to 60 mm Hg. Prophylactic injection of 20 mg/kg Ca and Cb and 3.3 mg/kg HTDP prevented cerebral blood flow autoregulation disturbance caused by transitory brain ischemia.

[The effect of lithium derivatives of GABA on blood circulation and metabolic indices in the brain under ischemia]. / Vliianie litievykh proizvodnykh GAMK na krovoobrashchenie i nekotorye pokazateli metabolizma v golovnom mozge v usloviiakh ishemii.

In acute experiments on anesthetized cats with cerebral ischemia in conditions of autohemoperfusion of cerebral and peripheral vessels with a stable volume of blood we found that lithium oxybutirate and new GABA derivatives: LOS 1-84 and LOS 5-79 affect the cerebral blood flow and metabolism in the brain. Prophylactic intravenous injection of lithium oxybutirate did not affect the development of postischemic hyperperfusion but inhibited postischemic hyperperfusion. The compounds prevent the development of postischemic phenomena and promote the recovery of metabolism in the brain.

[The effect of cytochrome c preparations on the cerebral circulation in cerebral ischemia]. / Vliianie preparatov tsitokhroma c na mozgovoe krovoobrashchenie pri ishemii mozga.

Biotechnological cytochrome c, heme-tetradecapeptide (HTDP) and animal cytochrome c were studied for their effects on intact and brain ischemic rats. In the latter case, the compounds were administered before ischemia induction and 15 min after artery ligation. It was found that the cytochrome c preparations did not virtually affect the cerebral circulation in intact rats. In cerebral ischemia, the cytochrome C preparations increased circulation, showing their more profound effects in case of preadministration of the drugs. The dose-independent effects of HTDP may be associated with the higher transmembranous permeability and the saturation phenomenon of this compound.

[Cerebral blood circulation during angiotensin-converting enzyme inhibition]. / Mozgovoe krovoobrashchenie v usloviiakh ingibirovaniia angiotenzin-konvertiruiushchego fermenta.

The inhibitor of angiotensin-converting enzyme captopril does not change the tone of the brain vessels but decreases the blood pressure and the tone of peripheral vessels, increases the oxygen and glucose demand in the brain in intact cats. In animals with brain ischemia, captopril decreased the tone of the brain vessels and promoted normalising of metabolic and transcapillary exchange in the brain.

[The comparative characteristics of the hemodynamic and biochemical indices of the postischemic period in relation to the regimens of brain autohemoperfusion]. / Sravnitel'naia kharakteristika nekotorykh gemodinamicheskikh i biokhimicheskikh pokazatelei postishemicheskogo perioda v zavisimosti ot rezhimov autogemoperfuzii mozga.

In anesthetized cats, comparative characteristics of hemodynamics and biochemical indications of postischemic period in respect to autohemoperfusion with stable blood volume and perfusion pressure, were determined. Cerebral ischemia was caused by the 15-min stop of the perfusing pump or flowmeter and a decrease of systemic arterial blood pressure to 40 ml Hg. In the autohemoperfusion of brain vessels in stable volume or stable arterial pressure, a phasic postischemic phenomenon becomes obvious. The regularity of modifications of the glucose and oxygen consumption by the brain, concentration of lactate and pyruvate under different conditions of autohemoperfusion, was found.

[The role of dopamine in regulating the cerebral circulation in extreme conditions]. / Rol' dofamina v reguliatsii mozgovogo krovoobrashcheniia pri nekotorykh ékstremal'nykh sostoianiiakh.

In acute experiments on anesthetized cats, the perfusion of dopamine (100 micrograms/kg.min) during 35 minutes after cerebral ischemia inhibited the development of postischemic phenomena. Dopamine was found to exert a considerable effect on the oxidative metabolism in the brain. The responses of cerebral, peripheral vessels and systemic arterial pressure to dopamine (25 and 75 micrograms/kg) in conditions of blood autoperfusion with cooled blood did not differ significantly from those in normothermia. The problem of dopamine participation in the organism adaptive responses to extreme conditions, is discussed.

[The role of the dopaminergic component in the autoregulatory reaction of the cerebral vessels]. / Rol' dofaminergicheskogo komponenta v autoreguliatornykh reaktsiiakh mozgovykh sosudov.

Cerebral blood flow was measured in anesthetised white rats with the hydrogen clearance technique under different levels of arterial blood pressure before and after cerebral ischemia induced with the occlusion of the common carotid arteries during 12 min. The continuous i.v. infusion of dopamine improved the autoregulation of the cerebral blood flow in intact animals and restored it to the initial level in the rats with ischemia.

[Effect of dopamine on the blood circulation and metabolism in the brain during ischemia]. / Vliianie dofamina na krovoobrashchenie i metabolizm v golovnom mozge v usloviiakh ishemii.

In acute experiments on anesthetized cats under blood autoperfusion of cerebral and peripheral vessels with a stable volume of blood during cerebral ischemia there was revealed the vascular and metabolic effects of dopamine on cerebral circulation. Administration of dopamine by perfusion in a dose of 100 micrograms/kg/min for 35 min after ischemia inhibited the development of postischemic hypoperfusion of the brain and also eliminated postischemic hypotension. A significant effect of dopamine on oxidative metabolism of the brain was observed.

[The participation of dopamine in the vascular reactions and metabolic processes of the brain]. / Uchastie dofamina v sosudistykh reaktsiiakh i metabolicheskikh protsessakh golovnogo mozga.

The dopamine effect on the tension of perfused vessels and the arterial BP depended on its doses in acute experiments on anesthetized cats. Dopaminergic vasodilatory components in perfused vessels responses and the BP were determined with joint blockade of alpha- and beta-receptors. Oxygen and glucose consumption increased in the brain during continuous i.v. infusion of various doses of dopamine (5 mg/kg/min and 100 mg/kg/min). The effect of dopamine on blood circulation and cerebral metabolism mediated through adrenergic (alpha- and beta-) and dopaminergic structures, is discussed.

[Autoregulation of the cerebral blood flow in normo- and hypertensive rats under beta-adrenoreceptor blockade]. / Autoreguliatsiia mozgovogo krovotoka u normo- i gipertenzivnykh krys v usloviiakh blokady beta-adrenoretseptorov.

A disorder in the autoregulation of cerebral blood flow due to a drop of arterial blood pressure (shift to the right) occurred earlier in hypotensive rats than in normotensive ones. A beta-adrenergic blockade (obsidan) improved the autoregulation (shift to the left) in both normo- and hypertensive animals.

[Effect of komplamin and nikoshpan on brain circulation and metabolism in the postischemic period]. / Vliianie komplamina i nikoshpana na krovoobrashchenie i metabolizm golovnogo mozga v postishemicheskom periode.

Intravenous administration of komplamin to anesthetized cats before the brain ischemia or in the early period following ischemia prevents the development of the postischemic phenomenon of the cerebral blood flow nonrecovery and beneficially influences the cerebral metabolism: restores oxygen and glucose consumption by the brain, decreases pyruvic acid level in the arterial and venous blood, attenuates the phenomenon of acidosis. Nikoshpan improves the blood supply to the brain, restores oxygen and glucose consumption by the brain in the postischemic period only if administered before the brain ischemia.

[Effect of euphylline and no-shpa on cerebrovascular resistance and the survivability of animals after cerebral ischemia]. / Vliianie éufillina i no-shpy na tserebrovaskuliarnoe soprotivlenie i vyzhivaemost' zhivotnykh posle ishemii golovnogo mozga.

In acute experiments on anesthetized cats with total ischemia of the brain (15-minute arrest of blood autoperfusion of the cerebral vessels by a stable blood volume) it was shown that euphylline and no-shpa administered before ischemia or in the early period after ischemia inhibit or prevent the development of the postischemic phenomenon of non-recovery of the cerebral blood flow. The two drugs contributed to survival of albino rats following the brain ischemia produced by ligation of both carotid arteries.

[Effect of dibasol and several of its imidazo-analogs on the resistance of animals to gravitational overloading and the dynamics of the development of post-ischemic cerebrovascular phenomena]. / Vliianie dibazola i nekotorykh ego imidazoanalogov na ustoichivost' zhivotnykh k gravitatsionnym peregruzkam i dinamiku razvitiia postishemicheskikh tserebrovaskuliarnykh fenomenov.

Anesthetized and nonanesthetized animals (white rats and cats) were used to study the effect of dibasol and its new imidazo analogs (designated AKS-67 and AKS-87) on animal tolerance to gravitational effects and cerebral ischemia (ligation of both carotid arteries) as well as on systemic arterial pressure and tone of cerebral and peripheral vessels (resistographically) in the postischemic period. The drugs were administered 30-90 min before exposure. It was found that in nonanesthetized rats dibasol and AKS-87 increased tolerance to cranio-caudal acceleration and decreased it to caudo-cranial acceleration, whereas AKS-67 produced a distinct protective effect regardless of the vector. In anesthetized rats (bilateral carotid ligation) AKS-67 and AKS-87 increased acceleration tolerance and dibasol produced no protective effect. Dibasol enhanced postischemic hypotension while AKS-67 and AKS-87 delayed or completely arrested it. For aerospace medicine the drug AKS-67 is of particular importance because it increases significantly animal tolerance to acceleration and stabilizes arterial pressure in the postischemic period.