Changes in the functional state of spinal-cord cell structures under gravitational unloading

© 2016, Pleiades Publishing, Inc.The functional properties of the spinal-cord structures of experimental rats under a 7-day gravitational unloading were assessed using the method of transcranial magnetic stimulation. Hypogravity was modeled by hanging the animals by their tails in an antiorthostatic position. The gastrocnemius muscle potentials evoked by magnetic stimulation of the efferent structures of the spinal cord were registered. We found that gravitational unloading causes significant changes in motor-potential parameters and the central motor transmission time. We propose that the cause of the revealed transformations is afferent inflow limitation, first of all the motor type, as well as adaptation of the central nervous system to new conditions of motor activity

Large non-thermal contribution to picosecond strain pulse generation using the photo-induced phase transition in VO2

Picosecond strain pulses are a versatile tool for investigation of mechanical properties of meso-and nano-scale objects with high temporal and spatial resolutions. Generation of such pulses is traditionally realized via ultrafast laser excitation of a light-to-strain transducer involving thermoelastic, deformation potential, or inverse piezoelectric effects. These approaches unavoidably lead to heat dissipation and a temperature rise, which can modify delicate specimens, like biological tissues, and ultimately destroy the transducer itself limiting the amplitude of generated picosecond strain. Here we propose a novel non-thermal mechanism for generating picosecond strain pulses via ultrafast photo-induced first-order phase transitions (PIPTs). We perform experiments on vanadium dioxide VO2 films, which exhibit a first-order PIPT accompanied by a lattice change. We demonstrate that during femtosecond optical excitation of VO2 the PIPT alone contributes to ultrafast expansion of this material as large as 0.45%, which is not accompanied by heat dissipation, and, for excitation density of 8 mJ cm-2 , exceeds the contribution from thermoelastic effect by the factor of five.

Changes in the functional state of spinal-cord cell structures under gravitational unloading

© 2016, Pleiades Publishing, Inc.The functional properties of the spinal-cord structures of experimental rats under a 7-day gravitational unloading were assessed using the method of transcranial magnetic stimulation. Hypogravity was modeled by hanging the animals by their tails in an antiorthostatic position. The gastrocnemius muscle potentials evoked by magnetic stimulation of the efferent structures of the spinal cord were registered. We found that gravitational unloading causes significant changes in motor-potential parameters and the central motor transmission time. We propose that the cause of the revealed transformations is afferent inflow limitation, first of all the motor type, as well as adaptation of the central nervous system to new conditions of motor activity

Changes in the functional state of spinal-cord cell structures under gravitational unloading

© 2016, Pleiades Publishing, Inc.The functional properties of the spinal-cord structures of experimental rats under a 7-day gravitational unloading were assessed using the method of transcranial magnetic stimulation. Hypogravity was modeled by hanging the animals by their tails in an antiorthostatic position. The gastrocnemius muscle potentials evoked by magnetic stimulation of the efferent structures of the spinal cord were registered. We found that gravitational unloading causes significant changes in motor-potential parameters and the central motor transmission time. We propose that the cause of the revealed transformations is afferent inflow limitation, first of all the motor type, as well as adaptation of the central nervous system to new conditions of motor activity

Changes in the functional state of spinal-cord cell structures under gravitational unloading

© 2016, Pleiades Publishing, Inc.The functional properties of the spinal-cord structures of experimental rats under a 7-day gravitational unloading were assessed using the method of transcranial magnetic stimulation. Hypogravity was modeled by hanging the animals by their tails in an antiorthostatic position. The gastrocnemius muscle potentials evoked by magnetic stimulation of the efferent structures of the spinal cord were registered. We found that gravitational unloading causes significant changes in motor-potential parameters and the central motor transmission time. We propose that the cause of the revealed transformations is afferent inflow limitation, first of all the motor type, as well as adaptation of the central nervous system to new conditions of motor activity

Functional State of the Neuromotor Apparatus of the Gastrocnemius Muscle in Rat Under Microgravity: Effect of Spinal Cord Stimulation

© 2019, Springer Science+Business Media, LLC, part of Springer Nature. The aim of this study was the evaluation of the functional state of the neuromotor apparatus of the gastrocnemius muscle in rat under conditions of gravitational unloading, as well as in conditions of gravitational unloading combined with magnetic stimulation of the spinal cord. The electrical potentials of gastrocnemius muscle of the rat evoked by the stimulation of the sciatic nerve were recorded after a week of exposure the animal in the experimental conditions. Parameters of motor response and H-reflex were evaluated. It was found that gravitational unloading caused an increase of the reflex excitability of the motor centers of gastrocnemius muscle of the rat and magnetic stimulation of the spinal cord combined with unloading increased the intensity of transformations. In addition, it was registered the changes of the functional state of the muscle under conditions of gravitational unloading combined with the stimulation of the spinal cord. The detected transformations were probably associated with the activation of adaptation processes in the new motor environment (simulation of the microgravity, restriction of peripheral afferentation including the support afferentation)

Functional State of the Neuromotor Apparatus of the Gastrocnemius Muscle in Rat Under Microgravity: Effect of Spinal Cord Stimulation

© 2019, Springer Science+Business Media, LLC, part of Springer Nature. The aim of this study was the evaluation of the functional state of the neuromotor apparatus of the gastrocnemius muscle in rat under conditions of gravitational unloading, as well as in conditions of gravitational unloading combined with magnetic stimulation of the spinal cord. The electrical potentials of gastrocnemius muscle of the rat evoked by the stimulation of the sciatic nerve were recorded after a week of exposure the animal in the experimental conditions. Parameters of motor response and H-reflex were evaluated. It was found that gravitational unloading caused an increase of the reflex excitability of the motor centers of gastrocnemius muscle of the rat and magnetic stimulation of the spinal cord combined with unloading increased the intensity of transformations. In addition, it was registered the changes of the functional state of the muscle under conditions of gravitational unloading combined with the stimulation of the spinal cord. The detected transformations were probably associated with the activation of adaptation processes in the new motor environment (simulation of the microgravity, restriction of peripheral afferentation including the support afferentation)

Time-Dependent Effect of Sciatic Nerve Injury on Rat Plasma Lipidome

Neuropathic pain is a condition affecting the quality of life of a substantial part of the population, but biomarkers and treatment options are still limited. While this type of pain is caused by nerve damage, in which lipids play key roles, lipidome alterations related to nerve injury remain poorly studied. Here, we assessed blood lipidome alterations in a common animal model, the rat sciatic nerve crush injury. We analyzed alterations in blood lipid abundances between seven rats with nerve injury (NI) and eight control (CL) rats in a time-course experiment. For these rats, abundances of 377 blood lipid species were assessed at three distinct time points: immediately after, two weeks, and five weeks post injury. Although we did not detect significant differences between NI and CL at the first two time points, 106 lipids were significantly altered in NI five weeks post injury. At this time point, we found increased levels of triglycerides (TGs) and lipids containing esterified palmitic acid (16:0) in the blood plasma of NI animals. Lipids containing arachidonic acid (20:4), by contrast, were significantly decreased after injury, aligning with the crucial role of arachidonic acid reported for NI. Taken together, these results indicate delayed systematic alterations in fatty acid metabolism after nerve injury, potentially reflecting nerve tissue restoration dynamics