Characteristic differences of electrophysiological signals from corticospinal tract of rats at palinesthesia stage after anesthesia / 中华神经医学杂志

Objective To observe the amplitude,discharge frequency and interspike interval (ISI) changes of the electrophysiological signals from corticospinal tract (CST) of adult rats at palinesthesia stage after anesthesia to study their characteristic differences.Methods The microelectrodes were plugged into CST at T8 spinal section after the Sprague-Dawley rats were anesthetized with Chlorpent.The neuro-electrical signals were identified and recorded from CST by means of Cerebus system at 1,2 and 3 h after anesthesia,respectively.The characteristics of the recorded signals,including the amplitude,discharge frequency and ISI,were described with the help of Off-line sorter and Neuroexplorer softwares.Results The discharge frequency of the neuro-electrical signals in CST at palinesthesia stage (2 and 3 h after anesthesia) obviously increased as compared with that at narcotism (1 h after anesthesia).The wave amplitude decreased gradually following the times [(640.13±126.01) μVvs (200.44±19.53) μVand (144.49±22.52) μV].The ISIchangedfromlocalizationto dispersion.Conclusion Conspicuous characteristic differences of electrophysiological signals from CST of rats in palinesthesia stage after anesthesia,including the wave amplitude,discharging frequency and ISI,are noted.

Effective dose and time window of ginseng total saponins treatment in rat after traumatic brain injury / 中国应用生理学杂志

<p><b>OBJECTIVE</b>To investigate the neuroprotective effect, effective dose and time window of ginseng total saponins (GTS) treatment in rat after traumatic brain injury (TBI).</p><p><b>METHODS</b>The modified Feeney's method was used to establish TBI model in rat. GTS was treated intraperitoneally. The neurological function and histological morphology of brain tissue were observed.</p><p><b>RESULTS</b>Different doses of GTS were used 6 h after TBI. The neurological and histological results showed that: compared with the TBI group, significant efficacy was observed 2 - 14 days after injury with GTS treatment at 10, 20, 40, 60 and 80 mg/kg (P < 0.05); The effects of GTS at 20, 40, and 60 mg/kg were better than those of GTS at 10 and 80 mg/kg. During the research on the time window of GTS intervention, GTS (20 mg/kg) showed significant effect when used at 3 h and 6 h after TBI; however 12 h, 24 h after TBI, application of GTS did not exert any significant effect.</p><p><b>CONCLUSION</b>GTS intervention after TBI could reduce brain damage and promote recovery of the neurological function. Among doses of GTS 5 - 80 mg/kg, 20 - 60 mg/kg is the best dose limit. The effective time window of GTS is 6 h after TBI.</p>

Therapeutic efficacy of hyperbaric oxygen on traumatic brain injury in the rat and the underlying mechanisms / 中国应用生理学杂志

<p><b>OBJECTIVE</b>To investigate the effects of hyperbaric oxygen (HBO) treatment on the activation of astrocytes and the expression of glia-derived neurotrophic factor (GDNF) and nerve growth factor (NGF) in the brain after traumatic brain injury (TBI).</p><p><b>METHODS</b>54 male SD rats were randomly divided into three groups (n = 18): sham-operated, TBI and HBO treatment groups. TBI was induced with Feeney's method, bone window was opened without strike on the brain tissue in the sham-operated group. HBO group rats received HBO treatment for 60 min in the hyperbaric chamber containing O2 100% at 3 ATA. When neurological functions were measured 48 h after TBI, rats were decapitated, the brain water content of 18 rats was measured, 18 brains were sliced for the morphological observation after Nissl staining and for the immunohistochemistry staining of astrocyte markers glial fibrillary acidic protein (GFAP), vimentin and S100, and the other 18 brains of injured side were used for Western blot analysis of GDNF and NGF.</p><p><b>RESULTS</b>HBO treatment reduced the neurological deficit, brain water content and hippocampal neuronal loss. In the observed cortex and hippocampal area astrocytes were activated, the cell number of positive expression of astrocyte markers GFAP, vimentin and S100 was increased, and the expression of GDNF and NGF was elevated after TBI. However, these indices were all enhanced further after the HBO treatment.</p><p><b>CONCLUSION</b>It is suggested that HBO may be an effective therapy for TBI and upregulation of the expression of GDNF and NGF may underly the effect of HBO.</p>

Anti-motion sickness efficacy of the extracted mixture of Chinese medical herbs and its influence on the blood level of hormones / 中国应用生理学杂志

<p><b>OBJECTIVE</b>To investigate the anti-motion sickness efficacy and influence on the blood level of some hormones of a Chinese prescription composed of 10 herbs such as spina date seed.</p><p><b>METHODS</b>According to the report by Cramptom and Lucot, SD rats and Beagle dogs were rotated around a horizontal axis, and the rat behavior of pica for Kaolin and the latency to vomit in dog were observed. In addition, guinea pigs were rotated around a vertical axis, and the nystagmus was recorded. Blood levels of corticosterone, adrenocorticotrophic hormone (ACTH), corticotropin releasing hormone (CRH) and arginine vasopressin (AVP) in rats were measured with radioimmunoassay. The influences of the extracted mixture of herbs on these variables were simultaneously investigated.</p><p><b>RESULTS</b>Compared with control group, oral administration of the extracted mixture of herbs: (1) significantly inhibited the rat behavior of pica for Kaolin and prolonged the latency to vomit in dog dose-dependently; (2) decreased the frequency of nystagmus and mean slow phase speed in rat; (3) reduced the elevation of corticosterone, ACTH, CRH and AVP in rat blood induced by rotatory stimulation; and (4) these effects of the extracted mixture of herbs were almost identical to dimenhydrinate.</p><p><b>CONCLUSION</b>(1) The extracted mixture of Chinese Medicinal Herbs we used could inhibit motion sickness effectively. (2) This drug could reduce the blood levels of hormones of hypothalamic-pituitary-adrenocortical axis and AVP elevated by provocative rotatory stimulation.</p>

The relationship of the content of AVP and the expression of V1b receptors in some brain areas with the sexual difference in the susceptibility of motion sickness in rats / 中国应用生理学杂志

<p><b>OBJECTIVE</b>To measure the content of arginine vasopressin (AVP) and V1b receptor expression in the brain areas in rats of both genders and after rotatory stimulation and thereby, to identify the involvement of AVP in the mechanisms of motion sickness.</p><p><b>METHODS</b>SD rats were rotated about a horizontal axis for 30 min, the content of AVP and the expression of V1b receptors in some brain areas were then measured with radioimmunological analysis and immunofluorescent method respectively.</p><p><b>RESULTS</b>We proved that: (1) In female rats, the content of AVP in each area we measured in rotation group did not show any significant change compared with that in control group (P > 0.05). In male rats, the AVP content of control group in each area was higher than that of female rats, but reduced by rotatory stimulation in forebrain, diencephalon and pontine (P < 0.05 or 0.01), however, the changes in the cerebellum and medulla of rotation group were not significant (P > 0.05). (2) The positive cell number of V1b receptor expression in the supraoptic nucleus of female rats in rotation group was lower, but higher in the vestibular nucleus and area postrema than that in control group (P < 0.05 or 0.01). In male rats, the V1b receptor positive cell number in the supraoptic nucleus and vestibular nucleus of rotation group did not show significant change compared with that of control group (P > 0.05), but a slight increase in the medulla of rotation group rats was observed (P < 0.05).</p><p><b>CONCLUSION</b>The gender difference in the susceptibility of motion sickness is potentially associated with the discrepancies in AVP content in the forebrain, diencephalon and pontine, in the expression of AVP-V1 receptors in the vestibular nucleus and area postrema, and in responses to rotatory stimulation, and that the vestibular nucleus and area postrema may be the areas targeted by AVP V1 receptor antagonist for antimotion sickness.</p>

Experimental study of recording and analysing electrophysiological signals from corticospinal tract in rats / 中国应用生理学杂志

<p><b>OBJECTIVE</b>To explore the recording method of the electrophysiological signals in corticospinal tract (CST) of adult rats by plugging microelectrodes and analyze the characteristics of these signals. These could provide some valuable and basic neural electrophysiological information for further research of recovering and refunctioning after spinal cord injury.</p><p><b>METHODS</b>The microelectrodes were plugged into the corticospinal tract at the T8 spinal section of Sprague-Dawley rats and the neuro-electrical signals were identified and recorded from CST by means of the Cerebus System. The characteristics of the recorded signals were described with the help of the Offline sorter and Neuroexplorer softwares, including the wavelength, amplitude, discharging frequency, the synchrony among the multi-discharging units from the same electrode and two different electrodes, analysis of interspike interval (ISI), etc.</p><p><b>RESULTS</b>The continuous and steady spontaneous electrophysiological signals were recorded from CST. Three or four types of discharging signals originated from different discharging units were collected with each electrode. The waveform of the signals appeared bidirectional. The wavelengths were 0.6 - 1.3 ms with wave amplitudes at a grade of hundred microvoltage and high signal-noise ratios. The LFB staining proved that the electrodes were accurately plugged into the corticospinal tract.</p><p><b>CONCLUSION</b>The neuro-electrical signals at a grade of hundred microvoltage could be recorded stably from the corticospinal tract of rats by the Cerebus System with the microelectrodes, which provided valuable and basic neural electrophysiological information for further research on recovering and refunctioning after spinal cord injury (SCI) by analyzing the characteristics of electrophysiological signals.</p>

Cognitive quality of professional divers / 中华劳动卫生职业病杂志

<p><b>OBJECTIVE</b>To explore and analyze the cognitive quality of professional divers.</p><p><b>METHODS</b>165 professional divers were tested with Raven's Standard Progressive Matrices (SPM), 80.8 Neural Type Measuring Form, etc. with 230 common people, 49 sailors and 66 trainee divers as control.</p><p><b>RESULTS</b>There were significant difference among professional divers of different ages in the type of nerve activity, cognitive style, action stability, memory span, time reaction, the perception of space, act of attention and dark adaptation (P < 0.05); Over all, the cognitive quality of professional divers did not differ significantly in education level or working years (P < 0.05); Professional divers were superior to the common people in depth perception, cognitive style, act of attention, action stability, the perception of space and dark adaptation, but inferior to them in intelligence, memory span and time reaction (P < 0.05); There were significant difference in such cognitive indicators as the type of nerve activity, depth perception, kinesthetic memory, cognitive style, the perception of space and dark adaptation (P < 0.05); Compared with the trainee divers, professional divers were significantly better in the type of nerve activity, cognitive style, act of attention, action stability and the perception of space (P < 0.05).</p><p><b>CONCLUSION</b>As a specified profession, diving needs some particular cognitive quality, while the profession itself would affect professional divers' cognitive ability to a certain extent.</p>

Effect of ginseng total saponins on neuronal apoptosis in rats with traumatic brain injury / 中华神经医学杂志

Objective To observe the effect of ginseng total saponins (GTS) on neuronal apoptosis in rats with traumatic brain injury (TBI), and explore the underlying mechanisms of GTS in the treatment of secondary brain injury. Methods SD rats were randomly divided into sham-operated group, TBI group and GTS-treatment group (n=18). TBI models were established with the modified Feeney's method. Three h after the success of model making, 20 mg/kg GTS was given to the GTS-treatment group through intraperitoneal injection and the same amount of normal saline was given to the TBI group. Twenty-four hours after the success of model making, the rats were sacrificed; the brain water content was measured by wet-dry weight method; the morphological changes of neurons in the hippocampal area were observed under optical microscope after Nissl staining. The neuronal apoptosis and the protein expressions of bax, bcl-2 and caspase-3 in the cortex and hippocampus were determined by TUNEL and immunohistochemical technique, respectively. Results Compared with TBI group,treatment with GTS decreased the water content of the brain, alleviated the damage of hippocampal area,reduced the number of TUNEL positive cells and the bax and caspase-3 positive cells, and increased the number of bcl-2 positive cells. Conclusion GTS can exert a neuroprotective effect in rats with TBI.The underlying mechanism of this effect is potentially related to the elevation of expression of bcl-2 and reduction of expression ofbax and caspase-3, and thereby, restraining the neuronal apoptosis in the brain tissue.

Experimental study of therapeutic time window of L-serine against focal cerebral ischemia/reperfusion injury in rats / 中国应用生理学杂志

<p><b>OBJECTIVE</b>To observe the therapeutic time window of L-serine against focal cerebral ischemia/reperfusion injury in rats, and related mechanisms.</p><p><b>METHODS</b>Sprague-Dawley rats were randomly divided into six groups (n=6), sham-operation group, vehicle group, 3, 6, 12 and 24 h treatment group of L-serine. Focal cerebral ischemia was induced with the method of middle cerebral artery occlusion (MCAO) in rats, and reperfusion was emerged by removing the thread 2 h later. The treatment of L-serine (200 mg/kg ip) was begun at 3, 6, 12 and 24 h after MCAO respectively, and subsequently repeated once 12 h. The vehicle group was intraperitoneally injected with isodose normal saline. The neurological behavior score and cerebral infarction volume was measured 48 h after reperfusion. In addition, the contents of malondialdehyde (MDA), activity of superoxide dismetase (SOD), the levels of inflammatory cytokines (TNF-alpha, IL-6) and ultrastructure of neuron in brain tissue were investigated.</p><p><b>RESULTS</b>Compared with the vehicle group, treatments with L-serine both 3 and 6 h after MCAO decreased the neurology deficit score and infarct volume. Only neurology deficit score had been reduced 12 h after MCAO, while no neuropmrotective effects had been observed during 24 h. Furthermore, L-serine elevated the content of SOD, decreased the level of MDA, TNF-alpha and IL-6 in ischemic brain tissue, and alleviated the injury of the neuronal ultrastructure.</p><p><b>CONCLUSION</b>L-serine exerted a time-dependent neuroprotective effect on the brain after MCAO in rat. This effect might be possibly mediated through following mechanisms: lessening oxidative stress and reducing the release of inflammatory cytokines.</p>

Relationship among sexual differences of susceptibility to motion sickness, AVP levels of plasma and pituitary and V1b receptor expression of pituitary in rats / 中国应用生理学杂志

<p><b>AIM</b>To investigate the relationship among sexual differences of motion sickness (MS), AVP levels of plasma and pituitary and the expression of pituitary V1b receptors for further understanding of the MS mechanisms.</p><p><b>METHODS</b>The conditioned taste aversion (CTA) of 0.15% saccharin sodium solution (SSS) was served as MS model. 98 (49 male and 49 female) rats were used in this experiment, 50 for the detection of the AVP level in plasma and pituitary with radioimmunoassay (RIA), 12 for the observation of the number of V1b receptor-positive neurons in the pituitary with the fluorescence immunohistochemistry method, the rest for the evaluation of the expression of V1b receptor in the pituitary by Western blot.</p><p><b>RESULTS</b>With regard to male rats, decrease of the drinking volume of 0.15% SSS was greater in female rats after rotatory stimulation. The plasma AVP concentration of female rats was significantly higher than that of males under normal conditions, but reduced significantly after rotatory stimulation. However, no significant change was found in male rats. In addition, the pituitary AVP level of the female rats was significantly higher than that of the male rats under normal conditions, but decreased at 8 h and significantly at 24 h after rotation. Similarly, the pituitary AVP level of male rats also decreased significantly at 8 h after rotation, but this decrease was not comparable to that of the females. At 24 h after rotation the pituitary AVP level almost recovered in male rats. In the pituitary, which was related to the stress response, the V1b receptor-positive neurons and the expression level of V1b receptor in female rats were significantly higher than those of the male rats, but they decreased significantly after rotation, while no apparent change was detected in the male rats.</p><p><b>CONCLUSION</b>The changes of plasma and pituitary AVP and V1b receptor level of the pituitary after rotatory stimulation are different between male and female rats and the AVP secretion of the pituitary may be involved in the sexual difference in susceptibility to motion sickness.</p>

Protective effects of ginsenoside RB3 on hypoxic/ischemic brain injury and involved mechanisms / 中国应用生理学杂志

<p><b>AIM</b>To observe protective effects and involved mechanism of ginsenoside Rb3 on hypoxic/ischemic brain injury, using cultured hippocampal neurons, rat hippocampal slices and intact animals.</p><p><b>METHODS</b>(1) Mice were tightly closed in glasses of 150 ml, and then survival time of them was observed. (2) During simulated ischemia and after reoxygenation, changes of orthodromic population spikes (OPS) in the area CA1 of hippocampal slice were investigated. (3) By using histochemistry, the expressions of NOS in CA1 area of rat hippocampus after hypoxic exposure were observed. (4) Using LDH detection, tests of total NOS, iNOS and cNOS activity, the protective effects of ginsenoside Rb3 were investigated on cultured hippocampal neurons treated with hypoxia.</p><p><b>RESULTS</b>(1) Given ginsenoside Rb3 (10 mmol/L), mice survived significantly longer than that of control group. (2) The occurrence of HIP (hypoxic injury potentials) decreased after administration of ginsenosides Rb3 (60 micromol/L) in many slices, while the recovery rate and amplitude of OPS after reoxygenation were significantly higher than those of the control group. (3) In CA1 area of rat hippocampus, NOS-positive neurons increased at the end of 24 h hypoxia and further 24 h reoxygenation, while the number of NOS-positive neurons decreased after treatment with ginsenoside Rb3. (4) The LDH leakage rate of cultured rat hippocampal neurons increased at the end of hypoxia, while it decreased after treatment with Rb3. Moreover the total NOS, especially iNOS activity of these neurons also decreased.</p><p><b>CONCLUSION</b>Ginsenoside Rb3 has a significant protective effect on hypoxic-ischemic injury of neurons, and this involves the stabilization of the cell membrane, the inhibition of the expression and activity of NOS, especially iNOS activity.</p>

Effects and mechanisms of ginsenoside Rb3 on glutamate excitotoxic injury in cultured neurons of rat hippocampus / 中国应用生理学杂志

<p><b>AIM</b>To observe protective effects of ginsenoside Rb3 on glutamate excitotoxic injury in cultured hippocampal neurons and involved mechanisms.</p><p><b>METHODS</b>On cultured rat hippocampal neurons treated with glutamate at toxic concentration, we made the following investigations: by using MTT assay, LDH leakage detection, tests of total NOS, iNOS and cNOS activity, and the protective effects of ginsenoside Rb3.</p><p><b>RESULTS</b>Ginsenoside Rb3 can enhance the hippocampal neuronal viability, decrease the LDH leakage, elevate the viability of cNOS, and in the same time weaken iNOS's viability.</p><p><b>CONCLUSION</b>Ginsenoside Rb3 has the significant protective effects on glutamate excitotoxic injury. The involved mechanism may include antagonizing the injury of neuron membrane, inhibiting the viability of iNOS, and increasing the activity of cNOS.</p>

Effects of breath holding in air on cardiac responses in man / 体力科学

Healthy male subjects were asked to hold their breath in air at the tidal inspiratory level, and time-dependent changes in mean values of several parameters of cardiovascular function were studied. The heart rate increased abruptly after the beginning of breath-holding and then decreased slightly with time. The stroke volume (SV) remained significantly low until the end of breath-holding, so that the cardiac output was decreased in parallel. With regard to the systolic time interval, the totai eiectromechanical systole and the left-ventricular systolic time (LVET) were not significantly changed, whereas the pre-ejection period (PEP) was markedly prolonged. Therefore, ratios of PEP/LVET and SV/LVET were increased and decreased with time, respectively. As the systolic, and in particular the diastolic blood pressures were elevated, the pulse pressure was reduced. Ratios of the diastolic and systolic times in relation to the heart rate at rest, during breath-holding and during recovery after breath-holding were all proved to be described by a single regression curve. However, the ratios obtained for cycling exercise at various heart rates showed a marked shift above the curve. These results clearly indicate that cardiac performance is lowered during breath-holding in air.