Benzodiazepine receptors in the mammalian central nervous system

A. A. Bogomolets Institute of Physiology, Academy of Sciences of the Ukrainian SSR, Kiev. Translated from Neirofiziologiya, Vol. 20, No. 2, pp. 269–279, March–April, 1988.     

Integration of soluble tetrodotoxin-sensitive brain proteins with liposomal membranes

Interaction of tetrodotoxin-sensitive proteins of the soluble cytoplasmic fraction of mammalian brain with liposomes was studied. Tetrodotoxin-sensitive proteins were shown to be incorporated in an orderly transmembrane manner into liposomes of a particular chemical composition (phosphatidylcholine-phosphatidylserine-cholesterol, brain phospholipids-cholesterol).A. A. Bogomolets Institute of Physiology, Academy of Sciences of the Ukrainian SSR, Kiev. A. V. Palladin Institute of Biochemistry, Academy of Sciences of the Ukrainian SSR, Kiev. Translated from Neirofiziologiya, Vol. 16, No. 5, pp. 716–725, September–October, 1984.     

Associative connections of the cat parietal cortex

Interneuronal connections of area 7 of the cat parietal cortex with projection areas of the visual, auditory, and somatosensory cortex were analyzed by orthograde degeneration and retrograde transport of horseradish peroxidase methods. By combined investigation the cortico-cortical sources of afferentation of parietal area 7 could be precisely identified and concentration sites of neurons sending their axons into this area identified, and the morphological characteristics of these neurons could also be determined.A. A. Ukhtomskii Physiological Institute, A. A. Zhdanov Leningrad State University. Donetsk Medical Institute. Translated from Neirofiziologiya, Vol. 12, No. 1, pp. 13–17, January–February, 1980.     

Effects of allapinine on sodium currents in neurons isolated from the rat trigeminal ganglion and cardiomyocytes

The effects were investigated of allapinine, diterpene alkaloid on ionic currents in voltage-clamped trigeminal neurons and cardiomyocytes isolated from rats. Allapinine application was found to exert an inhibitory effect on inward tetrodotoxin-sensitive sodium currents without changing their voltage dependence. Potential differences between the mechanisms of antiarrhythmic action of diterpene alkaloids and standard antiarrhythmic substances are examined.A. A. Bogomolets Institute of Physiology, Academy of Sciences of the Ukrainian SSR, Kiev. Institute of Plant Chemistry, Academy of Sciences of the Uzbek SSR, Tashkent. Translated from Neirofiziologiya, Vol. 22, No. 2, pp. 201–206, March–April, 1990.     

Purification of soluble tetrodotoxin-sensitive protein from the cytoplasmic fraction of bovine brain tissue

Highly purified protein preparations promoting TTX-dependent sodium permeability in the liposomal membrane were separated from the cytoplasmic fraction of bovine brain tissue. The protein was purified using anion-exchange and separation chromatography and gel filtration. The separated protein was found to be a high-molecular acidic glycoprotein forming 55 kD subunits during denaturation under reducing conditions. It was thought to contribute to the formation of voltage-dependent sodium channels in the cell membrane.A. A. Bogomolets Institute of Physiology and A. V. Palladin Institute of Biochemistry, Academy of Sciences of the USSR, Kiev. Translated from Neirofiziologiya, Vol. 19, No. 2, pp. 202–209, March–April, 1987.     

Effect of phosphorylation on the functional properties of the sodium channel reconstituted into an artificial membrane

The phosphorylation by protein kinase A of cytoplasmic protein of bovine brain, reconstituted as liposome membrane, is studied. The reconstituted protein imitates the potential-dependent sodium channel. The effect of phosphorylation is shown to depend on the way in which the protein is reconstructed into the artificial membrane. Phosphorylation of channels reconstructed in the open state inhibits the rate of sodium ion flux, while phosphorylation of channels reconstructed in the closed state enhances the activating effect of veratrine and scorpion toxin.A. A. Bogomolets Institute of Physiology, Ukrainian Academy of Sciences, Kiev. A. V. Palladin Institute of Biochemistry, Ukrainian Academy of Sciences, Kiev. Translated from Neirofiziologiya, Vol. 24, No. 2, pp. 192–198, March–April, 1992.     

The role of structures of the ventrolateral medulla in cardiovascular regulation

Both optimum cardiac operating regime and the state of vascular tonus depend largely on the activity of chemically sensitive structures of the ventrolateral medulla.A. A. Bogomolets Institute of Physiology, Ukrainian Academy of Sciences, Kiev. Translated from Neirofiziologiya, Vol. 24, No. 6, pp. 717–735, November–December, 1992.     

Inhibitory and excitatory processes in thalamic motor nuclei neurons in the normal nigrostriatal dopaminergic system and following injury to it produced by N-methyl-4-phenyl-1,2,3,6-tetrahydropyridine

Excitatory and inhibitory processes in neurons of the thalamic anteroventral and ventrolateral (VA–VL) motor nuclei were investigated in two sets of experiments on cats anesthetized with Ketalar and immobilized by myorelaxant during the course of stimulation of the red nucleus region and following chronic administration of N-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP, 5 mg/kg i.m. over a 5-day period): It was found 48 h after the last MPTP injection that up to 48% neurons belonging to the substantia nigra pars compacta had been destroyed and that dopamine level had declined to 30% of that found in intact animals. In cats injected with MPTP inhibitory processes declined significantly in both duration and efficacy in VA–VL relay and non-relay neurons, while latency of orthodromic excitatory response to red nucleus stimulation declined. It is suggested that attenuation of dopamine-modulated GABA-ergic nigrothalamic influences underlies the low level of inhibition occurring.A. A. Bogomolets Institute of Physiology, Academy of Sciences of the Ukrainian SSR, Kiev. Institute of Endocrinology and Metabolism, Ukrainian Ministry of Public Health, Kiev. Institute of Organic Chemistry, Academy of Sciences of the Ukrainian SSR, Kiev. Translated from Neirofiziologiya, Vol. 21, No. 5, pp. 620–629, September–October, 1989.     

Antigenic similarity between cytoplasmic tetrodotoxin-sensitive protein and neuronal membrane proteins

Membrane proteins with a molecular weight of 290, 180, and 55 kDa were isolated using immunosorbent attached to sepharose and rabbit antibodies to cytoplasmic tetrodotoxin-sensitive protein from beef brain gray matter. A technique used for research into voltage-dependent sodium channels was applied to reconstruction of these proteins and investigation of toxin-dependent sodium flows through the lipoprotein membrane. Findings are interpreted as evidence of the similarity between cytoplasmic tetrodotoxin-sensitive protein and that of sodium channels at the cell membrane.A. A. Bogomolets Institute of Physiology, Academy of Sciences of the Ukrainian SSR, Kiev; A. V. Palladin Institute of Biochemistry, Academy of Sciences of the Ukrainian SSR, Kiev. Translated from Neirofiziologiya, Vol. 21, No. 4, pp. 485–489, July–August, 1989.     

Mechanoreceptor system of the respiratory center and its contribution to respiratory control

The mechanoreceptor system of the respiratory center (RC) includes airway mechanoreceptors together with their conducting pathways and bulbar neuronal structures conveying impulses from mechanoreceptors to the RCV.A. A. Bogomolets Institute of Physiology, Ukrainian Academy of Sciences, Kiev. Translated from Neirofiziologiya, Vol. 24, No. 4, pp. 351–368, May–June, 1992.     

Cortical and subcortical spreading depression in rats produced by focused ultrasound

Steady potential shifts produced by focused ultrasond were recorded in the cerebral cortex, hippocampus, thalamus, and caudate nucleus. Impulses of 50–100 msec duration were presented at a frequency of 5 and 10 Hz. Negative steady potential shifts were produced in each of the structures investigated, which gradually increased during rhythmic electrical reaction to reach –3 to –7 mV within 10–30 sec, often succeeded by a wave of spreading depression (SD). In each structure analyzed amplitude of SD waves measured 20–30 mV, lasting 30–40 sec in the cortex, the caudate nucleus and the thalamus, and 80–120 sec in the hippocampus. In unanesthetized and lightly anesthetized animals SD waves were on occasions the precursors of convulsive discharges forming under the action of focused ultrasound. Ultrasound at threshold doses proved ineffective for 5–7 min after the occurrence of an SD wave, but again evoked repeated SD waves once the refractory period had ended. Accordingly, local effects produced by focused ultrasound can result in functional blockage of the brain structures due to cortical and subcortical spreading depression.Institute of Higher Nervous Activity and Neurophysiology, Academy of Sciences of the USSR, Moscow. Institute of Brain Research, All-Union Research Center of Mental Health, Academy of Medical Sciences of the USSR, Moscow. N. N. Andreev Acoustic Institute, Academy of Sciences of the USSR, Moscow. Translated from Neirofiziologiya, Vol. 18, No. 1, pp. 55–61, January–February, 1986.     

Rhythmic background thalamic neuronal activity in patients with extrapyramidal motor disorders

The background activity of 123 thalamic neurons was recorded in 30 patients with motor extrapyramidal disorders applying microelectrode techniques to neurosurgical practice. Recordings were taken from the ventro-oral anterior and posterior thalamic nuclei and the adjacent reticular nucleus. A computer analysis was performed of neuronal activity in 44 units and plots produced of autocorrelation and spectral density functions. In patients with parkinsonism and double athetosis, rhythmic activity was found in 48% of cells. A wide variety of regular fluctuations in background neuronal discharges was noted: in the range of theta and delta rhythms (5–7 and 1–4 Hz respectively) with a periodicity of seconds (2–10 sec) and decaseconds (15–40 sec). It was thought possible that several types of regular waves may coexist: phenomena of 2 or 3 accelerated waves and reduced frequency of spike activity of differing periodicity were observed in eight neurons within the same train of spikes. The origin and significance of rhythmically occurring changes in thalamic neuronal spike activity are discussed.A. A. Bogomolets Institute of Physiology, Academy of Sciences of the Ukrainian SSR; Institute of Neurosurgery, Ministry of Public Health of the Ukrainian SSR. Translated from Neirofiziologiya, Vol. 19, No. 2, pp. 192–201, March–April, 1987.     

Modulation by polyamines of the phosphorylation of the channel-forming cytosol protein of bovine brain

It was shown that the protein from the cytoplasm of bovine brain cells, which possesses functional similarity to the protein of membrane potential-dependent sodium channels, is the substrate of cAMP-dependent phosphorylation. Polyamines appreciably inhibit the phosphorylation of cytosolic protein. Spermine proves to be the most active here; in a concentration of 5 mM the inhibition reaches 40%. A possible modulation by polyamines of the functioning of sodium channels in the cell is discussed.A. A. Bogomolets Institute of Physiology, Academy of Sciences of the Ukrainian SSR, Kiev. R. E. Kavetskii Institute of Problems of Oncology, Academy of Sciences of the Ukrainian SSR, Kiev. Translated from Neirofiziologiya, Vol. 23, No. 5, pp. 603–607, September–October, 1991.     

Effect of the alkaloid lappaconitine on ionic currents through the somatic membrane ofHelix pomatia neurons

The effect of the alkaloid lappaconitine on passive ion transport through the somatic membrane of identified neurons of the snailHelix pomatia was studied under voltage clamp conditions. In a concentration of 4 mM lappaconitine has a reversible blocking action on the calcium channels of the excitable membrane. To study the effect of the alkaloid on inward sodium currents a solution in which calcium ions were replaced by the equivalent number of magnesium ions was used. Lappaconitine has no appreciable effect on the inward sodium current.A. A. Bogomolets Institute of Physiology, Academy of Sciences of the Ukrainian SSR, Kiev. Institute of Chemistry of Plant Substances, Academy of Sciences of the Uzbek SSR, Tashkent. Translated from Neirofiziologiya, Vol. 11, No. 5, pp. 469–474, September–October, 1979.     

Action of thiamine on auditory evoked potentials in the guinea pig

A technique is proposed for quantifying the effects of physiologically active substances at the periphery of the auditory analyzer. It was found that applying 1×10^–11 to 1×10^–3 M thiamine to the membrane of guinea pig cochlear round window (fenestra rotunda) produces a rise in the amplitude and a reduction in the latency of the N₁ and N₂ components of auditory nerve action potentials, waves I and II of brainstem auditory evoked potentials occurring in response to an acoustic stimulus. It is suggested that this effect is produced by facilitated synaptic transmission at synapses between hair cells and spiral ganglia neurons under the action of thiamine penetrating into the cochlea.A. V. Palladin Institute of Biochemistry, Academy of Sciences of the Ukrainian SSR, Kiev. A. I. Kolomiichenko Research Institute of Otolaryngology, Ministry of Public Health of the Ukrainian SSR, Kiev. Translated from Neirofiziologiya, Vol. 18, No. 5, pp. 654–660, September–October, 1986.     

Functional characteristics of electroreceptors of the Turkestan catfish

Acute experiments to record spike activity from single fibers of the lateral line nerve of the Turkestan catfish revealed electroreceptor formations which, in their functional characteristics, were similar to the ampullated electroreceptors of other freshwater fish (the so-called small pit organs). The threshold intensity of the uniform electric field was 1 µV/cm. A voltage drop on the skin of the fish was shown to be an effective stimulus for the electroreceptors. A spike response to a change in the magnetic field was found for the first time in electroreceptors of freshwater fish. The threshold level of magnetic induction for a velocity of rotation of the permanent magnet of 1 m/sec was 2.9 · 10^–4 T. Temperature and mechanical sensitivity of the electroreceptors was determined. The biological significance of electroreceptors of the Turkestan catfish is discussed.I. P. Pavlov Institute of Physiology, Academy of Sciences of the USSR, Leningrad. M. I. Kalinin Andizhan Medical Institute, Ministry of Health of the Uzbek SSR. S. M. Kirov Murmansk Marine Biological Institute, Kola Branch, Academy of Sciences of the USSR, Dal'nie Zelentsy. Translated from Neirofiziologiya, Vol. 12, No. 5, pp. 508–516, September–October, 1980.     

Modification to the Hodgkin-Huxley equation as applied to the somatic membrane of mollusk giant neurons

A modified system of Hodgkin-Huxley equations was used to describe transmembrane ionic currents during fixed changes of membrane potential and generation of action potentials in the soma of mollusk giant neurons. The effect of the axon was disregarded. The results of theoretical calculations are in satisfactory agreement with experimental results.A. A. Bogomolets Institute of Physiology, Academy of Sciences of the Ukrainian SSR, Kiev. Translated from Neirofiziologiya, Vol. 5, No. 3, pp. 315–322, May–June, 1973.     

Interaction between sea anemone toxin BgTX8 and ionic channels of neurons isolated from mammals

The action of the toxin BgTX₈ separated from the sea actiniaBunodosoma granolifera on transient tetrodotoxin-sensitive sodium and outward potassium currents of units isolated from rat sensory ganglia was investigated using techniques of voltage clamping at the membrane and intracellular perfusion. It was found that BgTX₈ decelerates the inactivation kinetics but has little effect on activation kinetics of sodium current. At the same time, a 5–10% increase in the amplitude of inward current was often observed at holding potentials of about –100 to –120 mV at the membrane. The dissociation constant of the receptor-toxin equals 4×10^–6 M and is adequately described by Langmuir's isotherm. It was also established that intracellular perfusion of neurons with anemone toxin-containing solution leads to a reduction in the amplitude of sodium current and decelerates its inactivation process. Suppression of outward potassium current was also noted.A. A. Bogomolets Institute of Physiology, Academy of Sciences of the Ukrainian SSR, Kiev. Institute of Brain Research, Academy of Sciences, Havana, Cuba. Translated from Neirofiziologiya, Vol. 20, No. 1, pp. 32–37, January–February, 1988.     

Modelling action of ionic channel blockers on postsynaptic currents

A mathematical model of the effects of open (ionic) channel blockers on generation of postsynaptic current at the neuromuscular junction is described. Quantitative aspects of simple blocking action are analyzed as well as criteria by which blockade of ionic channels may be discriminated from modification of their activation kinetics. Results of simulation are compared with experimental data. Some effects of channel-blocking substances following cholinesterase inhibition are examined.I. M. Sechenov Institute of Evolutionary Physiology and Biochemistry. Leningrad. S. V. Kurashov State Medical Institute, Kazan'. Translated from Neirofiziologiya, Vol. 21, No. 4, pp. 476–484, July–August, 1989.     

Low-threshold region of action potential generation in the somatic membrane of molluscan neurons

Heterogeneity of the somatic membrane of subesophageal ganglionic neurons ofHelix lucorum was studied by extracellular electrical stimulation. A sinusoidal current was applied through electrodes movable relative to the preparation. The threshold of action potential generation was shown to depend on the direction of the extracellular current, so that the presence of functional heterogeneity could be demonstrated in the cell soma.Institute of Chemical Physics, Academy of Sciences of the USSR, Moscow. Research Institute for Biological Testing of Chemical Compounds, Ministry of the Medical Industry of the USSR, Staraya Kupavna, Moscow Region. Translated from Neirofiziologiya, Vol. 17, No. 1, pp. 15–19, January–February, 1985.