Genetic models of impaired prestimulus inhibition of the shudder reaction

Prestimulus inhibition of the fear reaction (weakening of reflex shudder when the standard sound stimulus is preceded by a weak sound) was studied in eleven inbred mouse strains. Inhibition is regarded as a selective suppression of sensorimotor reactions typical of schizophrenia. Considerable genotype-related, differences were revealed in this inhibition. The reaction was not observed in DBA/2 mice and was weak (31%) in PT mice. Inhibition, of the shudder reflex was practically the same (54.8%) in mice with abnormal behavior: C57B1 (high inclination to alcohol) and CBA (predisposition to catalepsy). There was no correlation between reflex shudder and prestimulus inhibition. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 126, No. 7, pp. 86–89, July, 1998     

Depression of presynaptic inhibition of spinal reflexes by ammonium acetate

In experiments on cats ammonium acetate (AA), injected intravenously (2–4 moles/kg), depresses primary afferent depolarization (PAD), which is associated with presynaptic inhibition of spinal reflexes. Depression of PAD develops parallel with depression of postsynaptic inhibition of monosynaptic reflexes and is reversible in character. Depression of PAD is not connected with blocking of negative postsynaptic dorsal cord potentials or of reflex electrical discharges in ventral roots. It is concluded that one of the mechanisms of the convulsant action of AA is its depression of presynaptic inhibition. It is suggested that depression of PAD by AA may be the result of blocking of the chloride pump which operates in afferent terminals and creates the emf for the outward transmembrane chloride current producing PAD.Department of Pathological Physiology, N. I. Pirogov Second Moscow Medical Institute. (Presented by Academician of the Academy of Medical Sciences of the USSR A. D. Ado.) Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 84, No. 10, pp. 428–431, October, 1977     

Effect of autologous sera on mitogenic stimulation of peripheral blood lymphocytes of mini-pigs chronically intoxicated with alcohol

There are no statistically significant differences in the stimulation index for purified lymphocytes of control mini-pigs and mini-pigs with chronic alcohol intoxication. Autologous sera of control and experimental animals strongly suppress mitogen-induced blast transformation of lymphocytes without death of these cells. There are no statistically significant intergroup differences in the absolute number (per mm³) of T lymphocytes in peripheral blood. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 118, N ^o 7, pp. 89–91, July, 1994 Presented by N. K. Permyakov, Member of the Russian Academy of Medical Sciences     

Temperature dependence of acetylcholine esterase activity in synaptic membranes from rat brain during hypothermia

The degree of substrate inhibition of acetylcholine esterase activity decreases in plasma synaptosome membranes isolated from the cerebral cortex of rats subjected to short-term and prolonged hypothermia at 20°C, while activation energy and breakpoint of the temperature curve in the Arrhenius coordinates remain unaffected. The observed changes are supposed to compensate the inhibitory effect of hypothermia on enzyme activity. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 129, No. 3, pp. 326–328, March, 2000     

Effect of immunization against alcohol dehydrogenase on the behavior of white rats

Active immunization of white rats with alcohol dehydrogenase (horse ADH-1), a major ethanol-metabolizing enzyme shown to cause considerable and long-term inhibition of alcohol consumption, did not have adverse effects on their behavior. Rather, the rats showed enhanced motor and orienting-exploratory activities, developed conditioned responses (with both positive and negative reinforcements) more readily, and spent less time in a state of immobilization in the forced swimming test as compared with nonimmunized controls. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 118, N ^o 10, pp. 349–351, October, 1994     

Effect of the neurotoxin MPTP on behavior and cerebral content of neurotransmitters in mice

We compared the effects of the dopaminergic neurotoxin 1-methyl-4-phenyl-1,2,5,6-tetrahydropyridine (MPTP) on exploratory behavior and conditioning in C57B1 and outbred animals. Two intraperitoneal injections of MPTP suppressed the orienting and exploratory behavior in C57B1 (reductions of both horizontal and vertical motor activity), but not in outbred mice, and impaired conditioning. The data indicate the dopaminergic nature of learning disturbances and suggest that the MPTP model may hold a lot of promise for the search for new drugs for the treatment of cognitive disorders in Parkinsonism. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 128, No. 11, pp. 532–534, November, 1999     

Nociceptive muscle reflex responses in human forearms

In healthy volunteers, 5-min noxious stimulation with rectangular electrical pulses applied transcutaneously to the phalanges enhanced tonic activity in the palmar and finger flexor muscles resulting in a specific electromyographic pattern consisting of two successive bursts of activity which appeared after a period of inhibition. In patients with chronic pain in the arm, significantly lower thresholds for the first and the second waves of reflex activity have been found. This electromyographic pattern of the forearm muscle reflex responses is supposed to be similar to the nociceptive flexor reflex in the leg. It can be useful for objective assessment of the effectiveness of analgesia and pain syndrome therapy in patients with cervical spinal cord injury. Translated fromByulleten' Eksperimental'noi Biologii I Meditsiny, Vol. 126, No. 9, pp. 278–282, September, 1998     

Importance of the time of bone marrow transplantation for manifestation of allogeneic inhibition of stem cells

The effect of duration of the interval (4–96 h) between irradiation of F₁ (CBA×C57BL/6) hybrids and transplatation of bone marrow from C57BL/6 mice on manifestation of allogeneic inhibition of the stem cells was studied. In this particular donor-recipient model the degree of allogeneic inhibition was 90%. Transplantation of bone marrow carried out 4–48 h after irradiation had no effect on the number of colonies in the spleen of the F₁ hybrids. Considerable abolition of allogeneic inhibition (33%) was observed if the parental cells were injected 96 h after irradiation. Remote transplantation had no effect on the number of colonies in the spleen of syngeneic recipients.Laboratory of Experimental Genetics, Institute of Medical Genetics, Academy of Medical Sciences of the USSR, Moscow. (Presented by Academician of the Academy of Medical Sciences of the USSR N. N. Zhukov-Verezhnikov.) Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 81, No. 3, pp. 347–348, March, 1976.     

Effects of some different pulse parameters on bladder inhibition and urethral closure during intravaginal electrical stimulation: an experimental study in the cat

Intravaginal electrical stimulation (IVS) was used in the cat to induce bladder inhibition and urethral closure. The purpose of the study was to compare the efficacy of alternating constant-voltage pulses of different durations (0·1, 0·2, 0·5 and 5 ms) with that of chopped alternating pulses, each consisting of a train of five 0·5 ms pulses with 0·5 ms pauses between. The voltage requirement for an equal biological effect was lowest for the 5 ms alternating pulse, whereas the pulse power dissipation was lowest for the 0·1 ms pulse, about 10 per cent of that for the 5 ms pulse. If both voltage requirement and power dissipation are taken into account, the 0·5 ms pulse was considered the most appropriate compromise. The chopped pulse was the least efficient stimulus, since the threshold voltage was comparable to that of the 0·5 ms duration alternating pulse, implying a five times higher power dissipation. For bladder inhibition, the optimal stimulation frequency for alternating pulses was 10 Hz, both in terms of threshold voltage and power consumption. For urethral closure the voltage requirement was lowest at 50 Hz but 20 Hz was preferable in terms of power dissipation for an equal, although submaximal, effect.     

Surface architectonics of peripheral blood erythrocytes in patients with mental diseases

Scanning electron microscopy demonstrated altered surface topography of peripheral erythrocytes in patients with nonpsychotic mental diseases, nonmetabolic mental retardation, and paranoid schizophrenia. Maximum decrease in the number of bioconcave diskocytes and acculation of transitional, prehemolytic, and degenerative forms of erythrocytes were found in schizophrenia. Translated fromByulleten’ Eksperimental’noi Biologii i Meditsiny, Vol. 130, No. 10, pp. 429–432, October, 2000     

EMG responses in humans during painful heterosegmentary stimulation

The amplitude-temporal parameters of the nociceptive flexor reflex evoked in the upper and lower extremities by painful heterosegmentary electrical stimulation were studied in healthy volunteers. This reflex was detected bilaterally in the muscles of the upper and lower extremities independently of the site of painful stimulation. The maximum amplitude of the reflex was observed in the case, when the segmentary muscle innervation and the application site of painful stimulation coincided. The least latency of the nociceptive flexor reflex was observed after painful stimulation of the ear lobe. It was concluded the nociceptive flexor reflex is not an elementary polysysnaptic spinal reaction, but involves also some supraspinal centers. Translated fromByulleten’ Eksperimental’noi Biologii i Meditsiny, Vol. 130, No. 11, pp. 531–535, November, 2000     

Some properties of spastic ankle joint muscles in hemiplegia

Patterns of stretch reflex activities provoked by sinusoidal oscillations at the ankle joint were studied in hemiplegic patients. Three different patterns regarding tonic and phasic reflex activity were found to be typical for these patients. Rather than length-dependent inhibition, known from paraplegic and multiple sclerosis patients, a neutral effect or facilitation of stretch reflex was observed. The resistance to these movements was also studied at different muscle lengths. It was proved that the resistance to passive movements is highly dependent on the muscle length at which it is tested. It is therefore suggested that the value of resistance together with the muscle length should be documented.     

A method of analyzing of the “Dose-effect” dependence in multifactor medico-biological experiments

A conceptual-logical and mathematical approximation model has been created for the organism's response to external factors. The mathematical model of the “dose-effect” dependence for the combined effect of several factors is constructed using the basic equation of the Volterra mathematical theory of the struggle for existence. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 117, N ^o 3, pp. 328–331, March, 1994 Presented by L. A. Tiunov, Member of the Russian Academy of Medical Sciences     

Activity of NO-synthase and radical formation in rat brain compartments: Age dependence

The relationship between age and the activity of NO-synthase and generation of free radicals in different compartments of the brain was studied in male Wistar rats. No-synthase activity was highest in the cerebellum and lower in the cerebral cortex. It increased with age in the cerebellum and remained unchanged in the cortex, being virtually the same in the right and left hemispheres. Radical generation was much higher in the cerebellum than in the cortex and, as a rule, was age-dependent. The ratio of NO-synthase activity to radical generation was age-dependent: a tendency toward a positive linear correlation was observed in young animals, no correlation could be traced in adults, and a negative one was observed in old rats. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 120, N ^o 7, pp. 54–56, July, 1995 Presented by I. P. Ashmarin, Member of the Russian Academy of Medical Sciences     

Role of the specific determinant of group A streptococcus polysaccharide in inhibition of T-suppressor activity

Group A streptococcus polysaccharide is found to inhibit the activity of ConA-stimulated T suppressors. A-variant streptococcus polysaccharide, representing an L-rhamnose homopolymer which is identical to the rhamnose carcass of group A streptococcus polysaccharide, does not possess such an effect. The effect of group A streptococcus polysaccharide on the activity of T suppressors is considered to be associated with its determinant including N-acetylglucosamine as an obligatory component. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 119, N ^o 2, pp. 201–203, February, 1995 Presented by S. V. Prozorovskii, Member of the Russian Academy of Medical Sciences     

Optimization of research instrumental activity during exposure to a low-intensive conditioned stimulus

Research activity of rats is determined by the intensity of conditioned stimulus and probability of initially accidental correct performance of instrumental reaction during training in an arbitrary environment. If the values of this probability are unfavorable for training, attenuation of the intensity of conditioned stimulus causes a decrease in the research activity as a result of deterioration of conditions of information. By contrast, the values of probability of accidental correct performance of the reaction optimal for training promote a higher information significance of each research reaction, this decreasing the relationship between research activity and intensity of conditioned stimulus. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 126, No. 9, pp. 283–285, September, 1998     

Effect of temperature on guinea pig urinary bladder contraction mediated via P2X-receptors

In vitro experiments showed that P2X-receptor agonist α,β-methylene-ATP and electrical field stimulation in the presence of muscarinic and α-adrenoreceptors blockers induced contractile responses of isolated guinea pig bladder, which were more pronounced at 30°C than at 37°C or 42°C. P2x-receptor antagonist pyridoxal-6-phosphate-2′,4′-disulfonic acid, produced a more potent inhibitory effect on contractions induced by electrical field stimulation at 30°C in comparison with that at 37°C or 42°C while the contractions induced by α,β-methylene-ATP were similarly suppressed at all examined temperatures. Translated fromByulleten’s Eksperimental’noi Biologii i Meditsiny, Vol. 130, No. 10, pp. 407–410, October, 2000     

A new animal model of allodynia

A new rat model of allodynia is developed in which penicillin, an inhibitor of GABAergic inhibition, is applied to the dorsal surface of lumbosacral segments of the spinal cord. Correlation is found between abnormal pain reactions in rats with allodynia and alterations of evoked potentials in their dorsal horns. Stimulation of the sciatic nerve decreases threshold and increases amplitude and duration of evoked potentials. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 122, No. 9, pp. 258–261, September, 1996     

Effect of ethanol consumption on the expression of the tyrosine hydroxylase gene in rat brain and adrenals

After chronic alcoholization for 9 months with increased doses of ethanol, the tyrosine hydroxylase gene in the brain and adrenals of rats is expressed at different levels depending on the intensity of the desire for alcohol. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 124, No. 7, pp. 63–65, July, 1997