[Retrograde actions in the synapses forming the conditional connections and associations].

This article presents the evaluation different factors of retrograde activity in synapses during classical conditioning and formation of associations.

[Essentials of the neuron theory of subconscious and conscious decisions, evaluation of neuron mechanisms speed, reliability and trainability].

Essentials of the neuron theory of subconscious and conscious decision-making are demonstrated with reference to science literature. Basically, they are mutual inhibition of competing neurons representing different vectors of attention and action. Neuron pairs with direct inhibitory relations exist in reticular structures of the trunk, including the thalamus and hypothalamus, and in striatum.

[Job quality evaluation with regard to individual stress tolerance of operators].

Male test-subjects (n = 8, 25 to 36 years of age) were kept awake and working for 67 hrs. in an anechoic room. Every 1-2 hours the test-subjects performed eye-tracking of rhythmic light points with an abrupt and unexpected change of frequency.

[Inquiry into potential influence of the spaceflight factors on cerebral neurons and neural network (theoretical treatment)].

The article reviews literary data on the subject and discusses potentiality of spaceflight impacts on cerebral neurons, neural sequences and networks.

[Credible mechanisms of quick decisions and their reliability].

Theoretical analysis of the cerebral mechanism of quick subconscious and conscious decisions brings to the assumption that in the heart of this mechanism are networks of neurons representing various vectors of behavior (competitors); conscious decisions also recruit memory (consciousness) mechanisms cyclically coupled with the decision networks. The proposed pattern might explain some psychological factors (Miller number, Hick's law). The author highlights the factors for reliability of the quick decision mechanisms.

[Modulatory effects of various factors of muscular origin on the function of the motor nerve endings].

Muscle incubate was shown to contain factors capable to increase the transmitter release in low-effective synapses and decrease it in high-effective those, dueto activation and inhibition, respectively, of the processes governing formation of available store of the transmitter. Activatiory effect of the low-molecular fraction on the low-effective synapses was correlated with the concentration of histidine-containing substances in this fraction.

[The possible function of Schwann cells in neuromuscular transmission in the frog].

Anti-galactoside rabbit antisera increased the frequency of slow (atypical) MEPPs. No lysis of the Schwann cells was found in synaptic regions. The data obtained suggest that fixation of antibodies to galactocerebroside on the Schwann cell surface membrane alters the cell's activity thus affecting some characteristics of neuromuscular transmission.

[Effect of antibodies to glial glycolipid antigens on miniature end-plate potentials].

Less than 4% of miniature end-plate potentials (MEPPs) in frog cutaneous-pectoral muscles, normal or exposed to nonimmune rabbit serum were atypical. These MEPPs were of normal amplitude, but their time course was nearly twice as slow as that of normal MEPPs. The exposure of muscles to rabbit anti-galactocerebroside serum induced more than three-fold increase in the fraction of atypically slow MEPPs.

[Biochemical characteristics of a muscle perfusate and its effects on mediator release in the neuromuscular synapse].

Histidine-containing compounds (HCC) were found, using diazoreaction and reaction with diethylpyrocarbonate, a specific histidine reagent, in the perfusate of the frog hindlimb vasculature. After gel filtration on sephadex G-25 about 80% of HCC were eluted with a fraction with molecular mass less than 5000 kD. The studies of the perfusate influence on the characteristics of quantum secretion of transmitter in the preparation of frog cutaneopectoral muscle have shown that the perfusate increased the quantum content of end-plate potentials (EPP) due to increasing binominal parameter and decreasing frequency of miniature EPP.

[Effect of hyaluronidase on the end-plate miniature currents and potentials in the frog].

The effect of 0.1% hyaluronidase on miniature end-plate potentials and currents (MEPP and MEPC) was studied in the frog cutaneous-pectoris muscle. The action of hyaluronidase on armin-pretreated muscles caused a decrease in the amplitude, duration of half-decay time and rising phase of MEPPs and MEPCs.

[Paradoxical reactions of a neuromuscular preparation (on the 100th anniversary of their discovery by N.E. Vvedenskii)].

The discovery of the intensity of repetitive stimulation pessimum and of the paradoxical response to stregthening of stimuli in a parabiotic nerve, is presented in historical aspect. Both phenomena are shown to be based on the mutual electrical delay in propagated APs when the number of synchronously activated nerve fibers is increased. The delay may cause a propagation block through these nerve regions where the safety factor is diminished.

[Release of beta-alanine from the frog skeletal muscle determined by thin-layer chromatography].

The release of beta-alanine from the resting and contracting frog sartorius muscles was demonstrated by the two-dimensional thin-layer chromatography. The release of beta-alanine from indirectly stimulated muscles of frogs in winter was about 230% higher than at rest. When synaptic transmission was blocked by d-tubocurarine the release of beta-alanine from directly stimulated muscles did not exceed the release at rest.

[Miniature currents of the endplates of the muscle fibers of the diaphragm of the rat after inhibition of acetylcholinesterase with galanthamine].

Miniature end-plate currents (MEPC) in rat diaphragm were studied with voltage-clamp technique when synaptic acetylcholinesterase (AChE) was inhibited with different concentrations of galanthamine. The MEPC amplitude and time course were increased progressively with galanthamine concentrations in the range of 3.16 X 10(-8) - 10(-6) g/ml.

[Analysis of the paradoxical stage of neural cathodal parabiosis (the reciprocal inhibition of adjacent fibers)].

A preparation consisting of VIII-IX dorsal and ventral roots, the sciatic nerve and a single fiber of the tibial nerve was used to study changes in conduction reliability in a single nerve fiber by means of steady-state depolarization ("cathodal alteration") of the central part of the sciatic nerve: the depolarization led to a partial block of nerve fibers and to lowering of the safety factor in the single fiber tested. While a spinal root containing the fiber under study was stimulated with trains of stimuli (200/s) the number of APs traveling along the fiber depended on the stimulation strength, being maximal near the threshold. This suggests the influence of neighbouring fiber excitation on the conduction in the tested one.

[Sodium and potassium content of intrafusal muscle fibers and their resting membrane potential in different ionic media].

X-ray microanalysis revealed a high sodium concentration in intrafusal fibers of the frog-muscle whereas it appeared to be normal in extrafusal ones. Potassium concentration was practically the same both in intra- and extrafusal fibers which is in good agreement with the data obtained earlier with other techniques. Electrophysiological experiments demonstrated a similar behaviour of the resting MP found in both kinds of fibers in solutions with different ionic composition.

[Antidromic action of potassium in the neuromotor synapse].

The possibility of potassium accumulation in the synaptic cleft and a participation of its antidromic action in the regulation of presynaptic processes were estimated in experiments on neuromuscular junctions of the frog. In potassium-enriched solution, the reversal potential obtained by the linear extrapolation from the region of high membrane potentials was considerably altered according to the Takeuchi equation. The change of the reversal potential obtained by interpolation was insignificant as predicted by the Goldman--Hodgkin--Katz equation.