[Characterisation of enucleated cells apoptosis: human platelets and erythrocytes].

Apoptosis is a common mechanism of programmed cell death in virtually all nucleated cells. In spite of the fact that platelets and erythrocytes are the only enucleated cells in mammals they contain most of the apoptosis machinery of other cells and undergo similar apoptotic processes as nucleated cells except those connected with nuclear and chromatin transformation. Here we compare the mechanisms of platelet and erythrocytes apoptosis induced by different stimuli namely, stimulation ofthrombin and collagen receptor (T/C), inhibitor of BclX family proteins (ABT-373) for platelets, tert-butylhydroperoxide (tBH) and calcium ionophore (A-23187) for erythrocytes. Induction of platelet apoptosis by both methods (T/C and ABT-373) lead to strong phosphoetydilserine (PS) externalization, loss of the mitochondrial membrane potential (DeltaPsim), proteolytic cleavage of some cytoskeletal and regulatory proteins, and microparticle (MP) formation. However, there are clear differences between mechanisms of platelet apoptosis induced by TC and ABT-373. T/C induced apoptotic reaction is very fast (reach the maximum at 5 min), whereas ABT-373 induced reaction is more prolonged (first apoptotic evidence appears only after 30 min and reach the maximum after 3 hours). MP formation is much more pronounced in T/C than in ABT-373 stimulated platelets, whereas caspase 3 activation is much more stronger in ABT-373 than in T/C stimulated platelets. The main differences between these two apoptotic pathways are connected with aIIbp3 integrin, which activation appears only after T/C stimulation. For tBH experiments on erythrocytes we established optimal conditions (0.25x1012 cells/L, and strong, 1500 RPM stirring) for elucidation of apoptotic processes and found two independent ways of erythrocytes apoptotic processes; calcium independent, connected with met hemoglobin (metHb) formation (tBH stimulation), and calcium dependent pathway (A-23187 stimulation). Erythrocytes apoptosis induced by tBH is characterized by formation ofmetHb, cell shrinkage, fast (95 % during 3 hours) PS externalization, yield of hemoglobin, probably by vesicle (MP) formation. These cells are transformed to stomatocytes, become highly rigid, and could not be lysed even in pure water. All these reactions are calcium independent. Whereas increase of intracellular calcium concentration by A-23187 connected with formation of exinocytes, less pronounced (17 % during 3 h, 35 % during 15 h) PS externalization and rigidity (lysed in 50 mOsm buffer).

[Role of NMDA and AMPA glutamate receptors in the mechanism of korazol-induced convulsions in mice]. / Issledovanie roli NMDA i AMPA glutamatnykh retseptorov v mekhanizme korazolovykh sydorog u myshei.

The potency of mono- and dikationic derivatives of adamantane and phenylcyclohexyl to prevent seizures induced in mice by intraperitoneal administration of 80 mg/kg pentylenetetrazol (corazol), was studied. Monocationic derivatives of phenylcyclohexyl, being the selective channel blockers of NMDA glutamate receptors, as well memantine and MK-801 in micromolar concentrations, prevented both clonic and tonic components of corazol-induced convulsions. Their dicatonic derivatives which are channel blockers of NMDA and AMPA types of glutamate receptors, failed to prevent clonic seizures but at submicromolar concentrations prevented the tonic extensions provoked by corazol. Evidently, convulsive action of corazol originating from suppression of GABA-ergic inhibition is realized through activation of glutamergic synaptic transmission, and NMDA receptors are mainly involved in genesis of clonic seizures whereas activation of AMPA receptors is important for the tonic component of the corazol-induced syndrome.

[Comparison of the anticonvulsant activity of organic mono- and di-cations and their potential to inhibit NMDA and AMPA glutamate receptors]. / Sopostavlenie protivosudorozhnoi aktivnosti organicheskikh mono- i dikationov s ikh sposobnost'iu ingibirovat' NMDA i AMPA glutamatnye retseptory.

Effects of mono- and dicationic derivatives of adamantine and phenylcyclohexyl were studied on: (i) open channels of NMDA and AMPA glutamate receptors in the experiments on the isolated rat brain neurones, and (ii) convulsions induced by intraventricular injections of NMDA or kainate in mice. Monocations inhibited the NMDA receptors in vitro and prevented convulsions induced by NMDA in vivo, but failed to affect both the AMPA receptors and kainite-induced convulsions. Dications (IEM-1754 and IEM-1925) revealed both anti-NMDA and anti-AMPA potency in vitro, were highly effective against kainite-induced convulsions and excelled monocations in preventing the NMDA-induced ones. Evidently some steps connected with the AMPA receptor activity are involved in the genesis of the NMDA-induced convulsions. Anticonvulsant potency of IEM-1754 and IEM-1925 is comparable with those of known NMDA receptor inhibitors: memantine and MK-801. The IEM-1754 and IEM-1925 show no side effects. An incomplete correspondence between the activity in vitro and in vivo found studying some derivatives, may be due to peculiarities of their pharmacokinetics.

[Ability of novel non-competitive glutamate receptor blocking agents to weaken motor disorders in animals]. / Sposobnost' novykh nekonkurentnykh blokatorov glutamatnykh retseptorov oslabliat' dvigatel'nye narusheniia u zhivotnykh.

Action of mono- and dication derivatives of phenylcyclohexyl was compared with effects of known NMDA-antagonists memantine and dizocilpine. Seizures induced with the NMDA were effectively prevented both by mono- and dications, whereas against the kainate seizures dication alone was effective. Anticataleptic activity was much stronger in monocations, and the side effect of the substances under study on motor co-ordination was obviously weaker than in dizocilpine. Thereupon, the phenylcyclohexyl derivatives might be regarded as potential means for treatment of parkinsonism and other motor disorders.

[Glutamate receptor antagonists attenuate experimental catalepsy in rats]. / Sposobnost' antagonistov glutamatnykh retseptorov oslabliat' éksperimental'nuiu katalepsiiu u krys.

A long-term akinesia induced by haloperidol used as an experimental model of catalepsy helped to reveal that a dicationic derivatives adamantane (IEM-1754) and phenylcyclohexyl (IEM-1925) exerted different degrees of inhibition of the haloperidol effect: the IEM-1754 proved to be not inferior to the most effective NMDA antagonist MK-801. A relatively low potency of the IEM-1925 may be due to its obvious equal effects both on the NMDA and the AMPA receptor channels. A good correlation between the anticataleptic effects of the glutamate antagonists and the NMDA receptor blocking activity, were found. The AMPA receptor blockade might negatively affect the anticataleptic potency of the drugs under study.

[Anti-arrhythmia effect of digoxin antibodies in experimental myocardial infarct (arrhythmogenic action of endogenous digoxin-like factor)]. / Protivoaritmicheskii éffekt antitel k digoksinu pri éksperimental'nom infarkte miokarda (ob aritmogennom deistvii éndogennogo digoksinopodobnogo faktora).

Suggesting endogenous digoxin-like factor (EDLF) to display arrhythmogenic activities in myocardial ischemia (MI), we studied the effect of anti-digoxin antiserum (ADS) on the ventricular fibrillation threshold (VFT) after the coronary ligation in cats and ventricular arrhythmias caused by MI in rats and chloroform-induced hypoxia in mice. Intravenous administration of ADS (5 mg/kg) enhanced VFT in cats with MI from 11.3 +/- 1.6 to 53.3 +/- 8.1 V (M +/- m; p less than 0.01) and significantly reduced ventricular arrhythmias in rats and mice. Our experiments on the isolated electro-stimulated rat atria demonstrated that EDLF is likely not to be an adrenergic cotransmitter in the heart. Possible mechanisms of the arrhythmogenic action of EDLF are discussed.

[The role of an endogenous digoxin-like factor in regulating blood circulation and in the origin of arrhythmia in myocardial ischemia]. / Rol' éndogennogo digoksinopodobnogo faktora v reguliatsii krovoobrashcheniia i proiskhozhdenii aritmii pri ishemii miokarda.

The history of the discovery of endogenous digoxin-like factor (EDF) is described and the role played by the substance in blood circulation regulation, in the pathogenesis of arterial hypertension is discussed. The authors provide their own data (both experimental and clinical ones) concerned with EDF participation in the pathogenesis of early ventricular fibrillations in acute myocardial ischemia. Experiments on rats demonstrated that myocardial infarction (MI) is marked by a negative linear correlation between the intensity of ventricular fibrillations and the activity of Na,K-ATPase of intact red blood cells (r = -0.84) that mirrors the content of circulating EDF. Administration to the animals of digoxin antibodies binding EDF resulted in the antiarrhythmic effect and in the recovery of the enzyme activity. The patients demonstrated, within the first day of MI, a 76-percent inhibition of the activity of Na,K-ATPase of red blood cells. A correlation was discovered between the enzyme activity and the capacity of protein-free supernatants of blood plasma for inhibiting Na,K-ATPase, which indicates the presence of circulating EDF in blood plasma.

[Pharmacological analysis of the regulation of the phase duration of the respiratory cycle]. / Farmakologicheskii analiz reguliatsii dlitel'nosti faz dykhatel'nogo tsikla.

The oxotremorine, arecoline, physostigmine, armine, hyoscine and amphetamine affected the inspiratory (Ti) and expiratory (Te) duration as well as the Ti/(Ti + Te) ratio in 20 anesthetized cats. M-cholinopositive agents decreased the Ti/(Ti + Te) ratio due to shortening of inspiratory duration and simultaneous lengthening of expiratory one. Changes in the blood pressure and Ti/(Ti + Te) patterns appeared to be similar. The difference between our data and the data obtained by means of iontophoretic application of the agents to identified respiratory neurons might be accounted for by the fact that the routine technique used to identify respiratory neurons was unreliable.

[Effect of arecoline on the structure of rest and active wakefulness in the catfish Ictalurus nebulosus]. / Vliianie arekolina na strukturu pokoia i aktivnogo bodrstvovaniia u karlikovogo somika Ictalurus nebulosus.

The investigation demonstrated, that in the representative of the Osteichthyes--Ictalurus nebulosus, the hematoencephalic barrier for quaternary ammonium compounds is strongly pronounced. The difference in ability of tertiary and quaternary cholinergic substances to penetrate from the blood into the brain of this fish can be used for study of the presence and functional role of cholinoreceptive brain neurons. The pharmacological analysis showed the presence of cholinoreceptive neurons in the fish brain, participating in the activity of the functional systems which generate the "swimming automatism"--rhythmic movements of the tail, that are not accompanied by progression of the body. Apparently, this "swimming automatism" is the element of the future paradoxical sleep, which appears in its complete form in birds and mammals.