高原鼠兔与达乌尔鼠兔食物资源维生态位的研究

作者于１９９３年在青海省刚察县年诺索玛地区发现高原鼠兔（Ｏｃｈｏｔｏｎａ ｃｕｒｚｏｎｉａｅ）和达乌尔鼠兔（０．ｄａｕｒｉｃａ）在布哈河谷二阶同域且重叠分布之现象,并从这两种鼠兔的食物资源利用出发,研究了其生态位关系问题。在食物资源维上的生态位宽度（ＰＳ）,高原鼠兔为０．４７４４,达乌尔鼠兔为０．４９６４,即它们具有相近似的生态位宽度。这两种动物的生态位在食物资源谱维上的重叠值（ＦＴ）为０．８０９     

Wiener analysis of spike transmission by identified molluscan neurons

A mathematical model of spike train transmission by identified molluscan neurons was obtained by Wiener analysis. Poisson-distributed sequences of near-threshold stimuli were used as input trains for model construction and testing. Assuming that the error of describing responses of the synapse-neuron system purely by mean outflow frequency is 100%, addition of a linear component to the equation of the model reduces this error to 25%, and addition of a term allowing for nonlinear properties of the system reduces it to 16%. Comparison of the standard error of predicted responses of the model to testing stimulus trains and of responses of a real neuron to these same trains showed that the prediction error with allowance for nonlinear properties does not exceed 21%. Choice of adequate criteria for comparing model and experimental results is discussed.A. A. Bogomolets Institute of Physiology, Academy of Sciences of the Ukrainian SSR, Kiev. Translated from Neirofiziologiya, Vol. 16, No. 1, pp. 49–54, January–February, 1984.     

Conducting pathways of the rabbit lumbar sympathetic ganglia

Conducting pathways of ganglia from the lumbar portion (L₃–L₅) of the sympathetic trunk in rabbits were studied by recording action potentials from nerves of the ganglia evoked by stimulation of other nerves of these ganglia, and by intracellular recording from single neurons. Besides the well-known system of descending preganglionic fibers, which enter the trunk through white rami communicantes and, as they pass through the ganglia, form synapses on ganglionic neurons, some preganglionic fibers were shown to enter the sympathetic chain through gray rami communicantes and to run in both ascending and descending directions, forming synaptic connections with neurons of the lumbar ganglia.A. A. Bogomolets Institute of Physiology, Academy of Sciences of the Ukrainian SSR, Kiev. Translated from Neirofiziologiya, Vol. 16, No. 2, pp. 247–254, March–April, 1984.     

Interaction of peanut agglutinin,a lectin specific for nonreducing terminal d-galactosyl residues,with embryonal carcinoma cells

Peanut agglutinin (PNA), a lectin specific for terminal d-galactosyl residues, was found to react with embryonal carcinoma cells, but not with their differentiated derivatives. Receptors for PNA were detectable at the surface of all cells of the quasinullipotent F9 line and on only 50% of the multipotent PCC3/A/1 line. The fraction of the PCC3/A/1 population which expresses the F9 antigen was found to be included in the subpopulation carrying the PNA receptors. PNA⁺ and PNA^? subpopulations of PCC3/A/1 were separated by a PNA-mediated reversible agglutination of PNA⁺ cells with rabbit erythrocytes. These subpopulations were essentially F9⁺ and F9^?, respectively.     

Selectivity of edta-modified calcium channels to monovalent cations

The characteristics of slow inward sodium currents arising in response to membrane depolarization were studied in experiments on isolated dialyzed neurons of the snailHelix pomatia when the calcium-chelating agent EDTA was added to the calcium-free external solution. Values of the relative permeability of the corresponding ionic channels, determined from the shift of the equilibrium potential, were: P_Na+:P_Li+: +=1.00:0.80:0.55:0.21. The ratio between these values for "fast" sodium channels was 1.00:1.04:0.44:0.19. The induced sodium current was blocked by D-600 and nifedipine, which block calcium channels, more effectively than the calcium current of the same membrane (the corresponding dissociation constants were 10^–5 and 0.8·10^–5 mole/liter for the induced sodium current compared with 2.6·10^–5 and 2.3·10^–5 mole/liter for the calcium current). It is postulated on the basis of these data that the calcium channels have a principal selective filter similar to that of sodium channels, but also an additional binding site for bivalent cations, which prevents entry of monovalent cations into the channel. The addition of calcium-chelating agents to the calcium-free external solution liberates this site and thereby modifies the calcium channel into a sodium channel.A. A. Bogomolets Institute of Physiology, Academy of Sciences of the Ukrainian SSR, Kiev. Translated from Neirofiziologiya, Vol. 14, No. 5, pp. 491–498, September–October, 1982.     

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.     

Action of calcium ions on channels of inward and outward currents in the molluscan neuron membrane

Changes in the characteristics of activity of sodium, calcium, and potassium channels in the surface membrane during variation of the calcium ion concentration in the extracellular and intracellular medium were investigated by the voltage clamp method during intracellular dialysis of isolated neurons of the mollusksLimnea stagnalis andHelix pomatia. Besides their direct role in passage of the current through the membrane, calcium ions were shown to have two actions, differing in their mechanism, on the functional properties of this membrane. The first was caused by the electrostatic action of calcium ions on the outer surface of the membrane and was manifested as a shift of the potential-dependent characteristics of the ion transport channels along the potential axis; the second is determined by closer interaction of calcium ions with the specific structures of the channels. During the action of calcium-chelating agents EGTA and EDTA on the inner side of the membrane the conductivity of the potassium channels is substantially reduced. With an increase in the intracellular free calcium concentration the conductivity is partially restored. The action of EGTA and EDTA on the outer side of the membrane causes a substantial decrease in the ion selectivity of the calcium channels and changes the kinetics of the portal mechanism. These changes are easily abolished by rinsing off the chelating agents or by returning calcium ions to the external medium. A specific blocking action of an increase in the intracellular free calcium concentration on conductivity of the calcium channels was found.A. A. Bogomolets Institute of Physiology, Academy of Sciences of the Ukrainian SSR, Kiev. Translated from Neirofiziologiya, Vol. 9, No. 1, pp. 69–77, January–February, 1977.     

Chromatographic separation, of extracellular acid phosphatase of tobacco cells cultured under Pi-supplied and omitted conditions

An extracellular acid phosphatase preparation of tobacco XD-6cells cultured in suspension was resolved into three fractionsby sequential chromatography. Two of these were neutral pyrophosphatasewith diesterase activity, having optimum pH at 6.8. The otheris a nonspecific acid phosphatase having optimum pH at 5.8.The latter was concluded to be involved in the increase in extracellularactivity upon Pi-depletion. (Received August 31, 1976; )