Effect of amiridine and tacrine,drugs effective in Alzheimer's disease,on synaptosomal neurotransmitter uptake

All-Union Research Centers for Safety of Biologically Active Substances. (Presented by Academician I. P. Ashmarin, Academy of Medical Sciences.) Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 113, No. 4, pp. 379–381, April, 1992,     

Effect of amiridine and tacrine on the functional degeneration of the isolated neuron

Amiridine and tacrine are found to have a concentration-dependent effect on the spontaneous activity of an isolated neuron from crawfish. Amiridine in a concentration of 1 μM reliably prolongs the lifetime of the neuron, whereas lower concentrations are inactive and a high concentration (10 μM) reduces spontaneous activity. Tacrine is unable to prolong the lifetime of the neuron. It is suggested that, unlike tacrine, the therapeutic effect of amiridine stems from its ability to prolong neuronal functioning. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 121, N ^o 1, pp. 52–54, January, 1996 Presented by Yu. A. Romanov, Member of the Russian Academy of Medical Sciences     

Effect of amiridine and tacrine on reuptake of neurotransmitters in experimental amnesia

It is demonstrated that a single administration of amiridine, tacrine, piracetam, and physostigmine has no effect on the reuptake of adrenalin, noradrenalin, dopamine, and glycine, or of γ-aminobutyric, glutamic, and aspartic acids. Scopolamine (single administration or a 20-day treatment) also has no effect on the reuptake of these neurotransmitters. Administration of amiridine to intact rats during a 20-day period leads to a decrease in the reuptake of dopamine and γ-aminobutyric acid. A course of amiridine therapy of rats after repeated administration of scopolamine results in a reduced reuptake of dopamine. Tacrine, piracetam, and physosostigmine exhibit no activity under the chosen experimental conditions. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 119, N ^o 5, pp. 512–514, May, 1995 Presented by Yu. A. Romanov, Member of the Russian Academy of Medical Sciences     

Effect of amiridine and tacrine on potassium currents in the nerve fiber

Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 116, N ^o 10, pp. 397–400, October, 1993     

Second messengers contribute to cholinoceptor modulation by amiridine inHelix lucorum neurons

The effect of amiridine on the local inward acetylcholine current and its volt-ampere characteristic are studied by the two-electrode method of membrane voltage clamp in identified RPa3 and LPa3helix lucorum neurons pretreated with forskolin, sodium nitroprusside, A23187, and EGTA. The results suggest that second messengers (Ca²⁺, NO, cGMP, and cAMP) are implicated in the amiridine-mediated regulation of cholinoceptors inHelix lucorum neurons. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 118, N ^o 11, pp. 470–473, November, 1994 Presented by Yu. A. Romanov, Member of the Russian Academy of Medical Sciences     

Effects of ethanol and acetaldehyde on isolated nerve ending membranes: Study by atomic-forced microscopy

A new method of fixation of native synaptosomes and synaptosomal membranes from rat striatum was applied for their visualization by atomic-force microscopy. A scheme for examination of the surface of biological material was developed, which helps to distinguish intact synaptosomes from washed synaptic membranes and evaluate damage to synaptic membrane surface caused by ethanol (25 mM) and acetaldehyde (50 μM). The proposed method can be used for evaluation of the damaging effects of ethanol and acetaldehyde on neurons. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 130, No. 9, pp. 356–359, September, 2000     

Action of tetanus toxin and colchicine on synaptic membranes of the rat cerebral cortex

Purified tetanus toxin (TT), in experiments in vitro, was shown to affect neither the Na,K-ATPase activity of the synaptic membrane fraction of the rat cerebral cortex nor the inhibition of Na,K-ATPase activity produced by electrical stimulation of a suspension of synaptic membranes, nor the binding of GABA-³H by synaptosomes. TT and colchicine (1 mM) reduced the osmotic sensitivity of the nerve endings. Colchicine, in low concentrations (10^–5 to 10^–3 M), does not affect Mg- and Na,K-ATPase but, in higher concentrations (10^–2 M), it inhibits the activity of both ATPases considerably.Laboratory of General Pathology of the Nervous System, Institute of General Pathology and Pathological Physiology, Academy of Sciences of the USSR, Moscow. Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 83, No. 2, pp. 139–142, February, 1977.     

Effects of ethanol and acetaldehyde on isolated nerve ending membranes: Study by atomic-forced microscopy

A new method of fixation of native synaptosomes and synaptosomal membranes from rat striatum was applied for their visualization by atomic-force microscopy. A scheme for examination of the surface of biological material was developed, which helps to distinguish intact synaptosomes from washed synaptic membranes and evaluate damage to synaptic membrane surface caused by ethanol (25 mM) and acetaldehyde (50 μM). The proposed method can be used for evaluation of the damaging effects of ethanol and acetaldehyde on neurons. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 130, No. 9, pp. 356–359, September, 2000     

Effect of ultralow doses of thyroliberin on microviscosity of lipid components of biological membranes

Effects of the regulatory peptide thyroliberin on microviscosity of lipid components of endoplasmic reticulum biological membranes in mouse hepatocytes were studied by electron paramagnetic resonance. Thyroliberin in a concentration of 10⁻³–10⁻¹⁸ M decreased microviscosity of surface layers of membrane lipids. This decrease was the most pronounced (30%) under effects of 10⁻¹⁰ and 10⁻¹⁶ M thyroliberin. Physiological effects of thyroliberin corresponded to its influence on the membrane structure. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 129, No. 1, pp. 38–40, January, 2000     

Effect of hydrolipophilic equilibrium of the muramyl dipeptide derivatives on their internalization and interactions in biological membranes

The interaction between two homologous muramyl dipeptide derivatives (β-heptylglycoside and β-hexadecylglycoside) and model membranes and internalization of these derivatives into K562 human erythroleukemia cells are studied. It is suggested that the difference in the interaction of these homologs with model membranes and in their immunomodulating activities result from different hydrolipophilic balance of these perorations. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 122, No. 12, pp. 658–661, December, 1996     

Comparative analysis of neuroprotective activity of new chemical agent Vp and piracetam

The effect of new agent Vp (9-butylamine-3,3-dimethyl-3,4-dihydroacridine-1(2H) hydrochloride) on lifetime of isolated mechanoreceptive crayfish neurons was evaluated by the duration of its impulse activity. Vp significantly and dose-dependently prolonged the lifetime of both spontaneously degrading neurons and neurons degrading under conditions of inhibition of various stages of the energy metabolism: glycolysis and oxidative phosphorylation. The effect of Vp in a concentration of 10⁻⁷ M surpassed that of amiridine. Piracetam also prolonged the lifetime of spontaneously degrading neurons, but only in very high concentration (10⁻² M). It is concluded that Vp possesses a neuroprotective activity. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 129, No. 4, pp. 430–433, April, 2000     

The effect of dialysis membranes on lipid peroxidation in the erythrocytes of patients with terminal renal insufficiency

The content of malonic dialdehyde is shown to be significantly increased in the erythrocytes of patients as compared to the control. During hemodialysis using a regenerated cellulose membrane, the level of malonic dialdehyde reliably increased after 30 min of treatment (p<0.05) and dropped to the initial level following 180 min of hemodialysis. The level of membrane malonic dialdehyde on the erythrocytes remained at the pre-dialysis level at the 30th and 180th min of hemodialysis when a polysulfone membrane was used. It may be assumed that the activation of lipid peroxidation is due to the interaction of cells with the dialysis membrane and can be considered as one of the markers of biocompatibility. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 118, N^ulo 11, pp. 460–462, November, 1994     

Effect of Ca<Superscript>2+</Superscript> gradient on the structure of sarcoplasmic reticulum membranes

The structure of sarcoplasmic reticulum membranes was studied in the presence of modeled transmembrane Ca²⁺ gradient corresponding to the status of Ca²⁺ depot at different stages of the muscle contraction-relaxation cycle in health and disease. Various sites of the membrane were characterized using spectral analysis of tryptophan, pyrene, and merocyanine-540 fluorescence without evaluating specific changes in the molecules of membrane components (Ca²⁺-ATPase, ryanodine receptor, and lipids). The transmembrane Ca²⁺ gradient modulates the protein-lipid interactions and structural characteristics of the membrane. The proposed model can be used for studies of the effects of pharmacologically active substances and endogenous regulators. __________ Translated from Byulleten’ Eksperimental’noi Biologii i Meditsiny, Vol. 144, No. 11, pp. 517–521, November, 2007     

Mechanism of action of the new cardiotonic suphan on calcium exchange in cardiomyocytes

Effects of suphan, a new cardiotonic agent containing succinyl tryptophan, on the entry of Ca²⁺ into rat cardiomyocytes, its intracellular compartmentalization, and its exit from these cells were evaluatedin vitro. It was found that the recorded sulfan-induced rise of intracellular calcium was due to Ca²⁺ entering the cell via L-type calcium channels, and that a reversible reduction of its concentration in the sarcoplasm occurred through its accumulation in the sarcoplasmic reticulum and was blocked by the specific Ca²⁺-ATPase inhibitor thapsigargin (10 μM). Suphan did not alter the activity of Na⁺/Ca²⁺ exchange in a concentration range of 5–150 μg/ml. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 122, No. 7, pp. 57–59, July, 1996     

The effect of delta-sleep-inducing peptide on the Ca-transporting system of the sarcoplasmic reticulum and activity of the myocardial antioxidant enzymes

It is demonstrated that immobilization stress against the background of lowered catalase activity impairs the function of the sarcoplasmic reticulum Ca pump, particularly at high Ca²⁺ levels. the membranes of intracellular Ca²⁺ depots are destroyed much more rapidly than in the control, which results in Ca²⁺ release. Administration of delta sleep-inducing peptide to control animals results in a 30% increase in catalase activity for an unchanged level of superoxide dismusase and markedly improves the function of the Ca-transporting system at elevated levels of free Ca²⁺. A long-term stress after administration of the peptide not only causes no damage to the Ca-transporting system but actually increases its efficiency (compared with the control) at a high catalase level. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 121, N ^o 3, pp. 248–251, March, 1996 Presented by G. N. Kryzhanovskii, Member of the Russian Academy of Medical Sciences     

Comparative study of Na-blocking properties of antiarrhythmic drugs on isolated rat cardiomyocytes

The effects of the antiarrhythmic preparations lidocaine, flecainide, and rhlocaine on sodium concentration in cardiomyocyte cytoplasm are studied using the Na-sensitive fluorescent probe SBFI. The Na-blocking effect of lidocaine and rihlocaine depends on the frequency of electrical stimulation of cardiomyocytes (0.2–1.0 Hz). The data suggest the possibility ofin vitro testing of novel antiarrhythmic drugs. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 123, No. 6 pp. 666–668, June, 1997     

Lipid peroxidation in the depolarization of synaptosomes

Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 115, N ^o 3, pp. 244–245, March, 1993