[Neuromuscular stimulation in conditions of vibrational physical activity for the prevention of osteoporosis]. / Neiromyshechnaya stimulyatsiya v usloviyakh vibratsionnoi fizicheskoi nagruzki dlya profilaktiki osteoporoza.

The review discusses the modern possibilities of non-drug rehabilitation of patients with osteoporosis. Osteopenia (osteoporosis) and osteoporosis-associated bone fractures are a global public health problem, and an intensive search is undergoing for new methods of treatment, prevention, diagnosis and screening of this disease. Innovative technologies for influencing bone remodeling using vibration training seem to be an effective method that allows you to simultaneously positively affect maintaining bone density, increasing muscle strength and improving coordination, especially in elderly patients. The evolution of study of the effects of intense neuromuscular stimulation under accelerated physical exertion, which began with fundamental work on experimental animals, now includes numerous clinical studies. Vibrational physical activity is one of the methods of biomechanical stimulation, which is considered as an innovative method in the field of rehabilitation and physiotherapy. The physiological basis of this effect is intensive neuromuscular stimulation, which causes a reflex reaction of skeletal muscles. This scientific review describes the results of both monotherapy and combined methods of exposure to vibrational stimulation using modern pharmacotherapy. Attention is focused on the positions of importance in the design of the study and the planning of rehabilitation programs of uniformly accelerated training.

[Significance of the composition of conduit internal environment for the activation of axon growth in patients with extended peripheral nerve defects]. / Znachenie sostava vnutrennei sredy konduitov dlia aktivatsii rosta aksonov pri protiazhennykh defektakh perifericheskikh nervov.

The recovery of peripheral nerves after injury is an urgent medical problem. Despite the advances in microsurgery techniques, it is still not possible to achieve complete holistic and functional recovery. It is more difficult to repair neural tissue after injury if there is a diastasis between the injured ends nerves. In this case, neurorraphy can not be carried out due to the eruption of the filaments in tension and convergence of proximal and distal ends of the axon. Modern tactics of restoration of extended defects of nerves involves the use of conduits - cylindrical conductors, overlapping posttraumatic diastasis, in order to create a vector of regeneration from the proximal part of the nerve to the distal. An ideal conduit should contain an internal environment that stimulates the recovery processes of nerve fibers. At present, there is no unified approach involving the use of a certain natural or artificial conduit environment. The review analyzes the regenerative potential of the internal environments of conduits as the most promising in modern biotechnologies for the reconstruction of extended peripheral nerve defects.

Integration of the Proprioceptive and Central Inspiratory Inhibitory Afferent Inputs by Pontine Noradrenergic A5 Neurons in Rats.

Inhibitory afferent inputs to pontine A5 noradrenergic neurons (A5 NN) are not known, except partial baroreceptor input. In spontaneously breathing pentobarbital-anesthetized rats, we registered 35 A5 NN that were activated by hypoxia (100% N2, 10 sec) by more than 5 times in comparison with the background. Cooling of retrotrapezoid nucleus (15°C, 6 sec) completely blocked the motor inspiratory output and A5 NN discharge frequency increased (23/23) by more than 7 times in comparison with the background values. The beginning of A5 NN activation coincided with cessation of inspiratory activity. Short-term passive stretching of the shin muscles (1 sec, 100 g) caused BP drop and complete inhibition of A5 NN (12/12) activated by hypoxia. Inhibitory afferent inputs from proprioceptors and central inspiratory neurons that can limit A5 NN activity were demonstrated.

[Recent medical techniques for peripheral nerve repair: nerve guidance conduits update].

The review deals with recent medical methods of reconstruction of peripheral nerve injuries, especially using the technology of nerve guidance conduits (NGCs), as well as scientific and applied prospects of further development of clinical and technical research in this area. In neurosurgery established techniques for the treatment of peripheral nerve injures include the matching and suturing of severed nerve fibers (however, it is important to avoid tension in gaps for effective regeneration of the nerve fiber), as well as allo/autologous nerve grafting for larger gaps (gold standard of repair). Unfortunately, this treatment is not always feasible in a number of clinical situations, has drawbacks and is associated with a potential risk of postoperative complications; in particular applying of donor transplants is complicated immunological incompatibility reactions. The use of implantable artificial tunneling device known as a nerve guidance conduit is an alternative method of reconstruction, contributing to the physiological regeneration of nerve fiber. The article describes technical engineering constructions - including by using various non- and biomaterials, liquid metals, light/laser, methods of electrospinning and microstereolithography - which are either commercially available or pre-tested and clinical studies detailing outcomes and reconstructive options. The review emphasizes that the further development of scientific research in the field of new materials and polymers, as well as techniques for the preparation and implantation of nerve conduits and their subsequent practical assessment is necessary for clinical medicine and rehabilitation.

NMDA Receptors of A5 Area in the Regulation of Blood Pressure and Respiratory Activity during Hypoxia in Rats.

In narcotized (40 mg/kg sodium ethaminal intraperitoneally) spontaneously breathing albino rats, experimental short-term hypoxia induced BP drop and increased phrenic nerve firing rate. Unilateral microinjection of a selective NMDA receptor blocker ketamine hydrochloride (50 nl; 4 mM) into A5 area did not affect BP and phrenic nerve fi ring rate. However, against the background of preliminary NMDA receptor blockage, hypoxia more markedly stimulated rhythmic activity of the respiratory center and hypotensive response. Unilateral microinjection of a selective blocker of non-NMDA receptors GAMS (50 nl; 4 mM) into A5 area did not change initial BP and phrenic nerve fi ring rate. The studied parameters in rats exposed to hypoxia after blockage of non-NMDA receptors in A5 area did not differ from the control levels. Thus, activity of the respiratory center and BP in rats during hypoxia is regulated by the structures in A5 area and NMDA glutamate receptors.

Role of NMDA- and non-NMDA subtypes of glutamate receptors in A5 neuronal structures in the regulation of respiration and circulation during thermal nociceptive stimulation in rats.

In narcotized albino rats, thermal nociceptive stimulation elevated systemic blood pressure and increased the frequency of respiratory rhythm generation. Unilateral microinjection of ketamine hydrochloride, a selective blocker for NMDA receptors, into A5 region did not change the baseline parameters of multineuronal activity in the phrenic nerve and systemic blood pressure. Under conditions of NMDA-receptor blockade, thermal nociceptive stimulation evoked more pronounced respiratory response (in comparison to that observed before ketamine treatment), but induced smaller blood pressure rise. Unilateral microinjection of GAMS, a selective blocker for non-NMDA receptors, into A5 region did not modify the examined baseline parameters and the nociceptive response. It is concluded that during thermal nociceptive stimulation, activity of the respiratory center and blood pressure in rats are controlled by neuronal structures in A5 region via NMDA subtype of glutamate receptors.

Effects of microinjections of glutamate and glutamate receptor antagonists into A5 zone on generation of respiratory rhythm in ponto-bulbospinal preparations from newborn rats in vitro.

Activation of glutamate receptors in A5 neurons enhanced their tonic inhibitory influence on the respiratory rhythm generator in isolated newborn rat ponto-bulbospinal preparations. The stimulating effect of glutamate on A5 neurons is determined by its effect mainly on non-NMDA receptors and less so on NMDA receptors.

Control of respiratory and hypotensive response during hypoxic chemoreflex by A5 region neurons in rats.

The responses of A5 region neurons, the phrenic nerve, and systemic blood pressure to short-term hypoxia were examined in rats under conditions of spontaneous respiration. Tonic and respiration-modulated neurons increasing their discharge activity during hypoxia were identified. This hypoxia-induced response was more pronounced in the neurons with baseline discharge rate of 0.1-4.5 Hz (electrical activity of neurons increased by 4-5 times) compared to neurons with the baseline activity of 5.4-49.6 Hz (discharge rate increased by 1.4-2.0 times). The latency and duration of activation of all types A5 neurons correlated with the parameters of activation of the phrenic nerve. During hypoxia, activation of A5 neurons corresponded to the period of blood pressure drop (one-third of the reaction time), but not to the period of plateau or recovery phase. Low-, middle, and high-frequency A5 neurons participated in the modulation of hypoxia-provoked respiratory and hypotensive responses. Modulation of the respiratory response by A5 neurons was observed during the entire period of phrenic nerve activation, while modulation of the hypotensive response occurred only during blood pressure decrease.

Nitric oxide in the A5 region modulates reaction of the respiratory center and blood pressure to hypoxia in rats.

Hypoxia was followed by more pronounced activation of the respiratory center and pronounced hypotensive response after unilateral injection of nitric oxide synthase blocker L-NAME into the A5 region. Microinjection of exogenous nitric oxide donor sodium nitroprusside into the A5 region abolished the effect of L-NAME on hypoxia-induced changes in activity of the respiratory center and blood pressure. Bilateral transection of the vagal and sinocarotid nerves suppressed the response of the respiratory center to hypoxia. However, the hypotensive response to hypoxia in these rats did not differ from that in intact animals. Under conditions of peripheral chemoreceptor deafferentation, the hypotensive response to hypoxia did not differ before and after blockade of nitric oxide synthase in the A5 region. The regulation of respiratory center activity and blood pressure during hypoxia was modulated by A5 neurons with the involvement of nitric oxide.

Involvement of rostral ventromedullar neuronal structures in nitric oxide modulation of central chemosensitive drive.

Surface perfusion of the rostral ventromedullar cerebral subdivisions with artificial cerebrospinal fluid containing exogenous NO donor sodium nitroprusside (0.1 mM) increased the discharge rate of the phrenic nerve and potentiated the response of the respiratory center to hypercapnia in narcotized mature rats. The latter reaction was prevented by blockage of NO-synthase in rostral ventromedullar neural structures with N(omega)-nitro-L-arginine methyl ester (L-NAME, 0.3 mM). It was hypothesized that rostral ventromedullar neural structures are involved in modulatory action of NO on central chemosensitive drive.

Respiratory activity of bulbospinal preparations from newborn rats subjected to periodic hypercapnia in the prenatal period.

Periodic exposure of pregnant rats to hypercapnia (10% CO(2)) delayed the development of mechanisms underlying respiratory rhythmogenesis in newborn animals during the early postnatal period. In vitro studies showed that rhythmic activity of the respiratory center in newborn rats (days 0-3) was 2-3-fold lower than that in intact preparations. Age-related changes of respiratory activity were absent, while the reactions of the respiratory center to CO(2) were suppressed compared to the control.

Role of NO-ergic mechanism in regulation of rhythmogenesis in respiratory center in bulbospinal preparation from newborn rat.

In vitro experiments on bulbospinal preparations isolated from newborn rats (postnatal days 0-4) demonstrated that exogenous and endogenous NO can modulate respiratory rhythm generation and change various spectral parameters of respiratory discharges.

Effects of nitric oxide on respiratory activity in bulbospinal preparation from rat fetus.

Experiments on bulbospinal preparations isolated from rat fetus (gestation days 18 and 21) showed that exogenous and endogenous NO can stimulate respiratory rhythm generation and change spectral characteristics respiratory discharges.

The involvement of rostral ventromedullary neuronal structures in regulating the mechanism of formation of the respiratory rhythm in rats.

The role of neuronal structures in the rostral parts of the ventral surface of the medulla oblongata of the rat in regulating the central inspiratory activity of the respiratory center was analyzed. It is suggested that neuronal structures of the subretrofascial area, located close to the ventral surface of the medulla oblongata have direct associations with the mechanisms generating and regulating the respiratory rhythm. These have excitatory effects on neurons of the respiratory center which generate inspiratory activity.