Effect of aquaporin-4 deficiency on intravenous anaesthetic induced hypnotic effects in mice / 生理学报

The deficiency of aquaporin-4 (AQP4) has been reported to alter release of neurotransmitters in the mouse brain. However, the functional relevance of AQP4 in mediating essential components of the general anaesthetic state is unknown. The aim of the present study was to investigate the role of AQP4 in general anaesthesia in mice lacking AQP4. The hypnotic effects of propofol, ketamine, and pentobarbital in AQP4 knockout (KO) and CD1 control mice were evaluated using the behavioural endpoint of loss of righting reflex (LORR). The effects of propofol on extracellular levels of amino acids in prefrontal cortex of freely moving mice were investigated using microdialysis coupled to high performance liquid chromatography with fluorescent detection. The result showed that, after receiving ketamine or pentobarbital, LORR occurred at earlier time in KO mice than that in control animals. Intraperitoneal injection of ketamine or pentobarbital increased the duration of LORR. After the administration of propofol, the duration of LORR was significantly reduced in KO mice compared with that in controls. Propofol increased the extracellular levels of aspartate, glutamate, and GABA, but not taurine, in prefrontal cortex. There were significant differences of increase patterns of the three kinds of neurotransmitters between KO and WT mice. Notably, the duration of GABA level increase correlated with the duration of LORR in two genotypes of mice. These results provide in vivo evidence of different responses in time-dependent release of excitatory and inhibitory neurotransmitters in prefrontal cortex of the two genotypes of mice. It is suggested that changes in anaesthetic reactions in mice with AQP4 loss may be related to neurotransmitter regulation, and that normal functioning of AQP4 plays an important role in the maintenance of anaesthetic hypnosis.

Learning resource exploration of anesthesiology postgraduate / 中华医学教育探索杂志

Thorough excavation and artful utilization of various kinds concrete and invisible learning resources contribute to the cultivation of excellent postgraduates.In postgraduate education of anesthesiology Xuzhou Medical College utilizes time,network,technique platform,research outcome,self-potentiality and clinical patients resources,which produces an active effect and has important instructional significance.

The effect of propofol preconditioning on cytochrome C release from mitochondria after mild hypothermic ischemia/reperfusion in isolated rat hearts / 中国应用生理学杂志

<p><b>AIM</b>To explore the effect of propofol preconditioning on cardiomyocyte apoptosis and cytochrome C release from mitochondria during mild hypothermic ischemia/reperfusion in isolated rat hearts.</p><p><b>METHODS</b>50 isolated SD rat hearts perfused on Langendorff apparatus were randomly divided into 5 groups (n=10): control group (C), DMSO group (D), 3 different concentrations of propofol groups of 25 micromol x L(-1) (P1), 50 micromol x L(-1) (P2), 100 micromol x L(-1) (P3) propofol respectively. All of the isolated rat hearts were subjected to 31 degrees C mild hypothermic ischemia for 55 min followed by 60 min reperfusion. The D, P1, P2, P3 groups were preconditioned by perfusing with K-H solution containing 20 micromol x L(-1) DMSO and 25, 50, 100 micromol x L(-1) propofol respectively for 10 min and then followed by 5 min K-H solution washing out before ischemia. The preconditioning procedure was repeated twice. Hemodynamics of the hearts was recorded after equilibration(baseline values) immediately before ischemia, 30 min and 60 min after reperfusion respectively. Cardiomyocyte apoptosis rate and contents of cytosolic and mitochondrial cytochrome C were measured at the end of reperfusion.</p><p><b>RESULTS</b>After 30 min and 60 min reperfusion, LVEDP was significantly lower and LVDP was significantly higher in P3 group than those in C group ( P < 0.05, P < 0.01). Compared with C group, cardiomyocyte apoptosis rate of the hearts decreased significantly in P2,P3 groups at the end of reperfusion (P < 0.05, P < 0.01). Cytochrome C level increased significantly in mitochondria but decreased significantly in cytosol in P2, P3 groups as compared with C group (P < 0.05, P < 0.01).</p><p><b>CONCLUSION</b>Propofol preconditioning decreased cardiomyocyte apoptosis, protected the heart against 31 degrees C mild hypothermic ischemia/reperfusion injury by attenuation of the release of cytochrome C from mitochondria to cytosol.</p>

Role of extracellular-signal regulated kinase cascade on cerebral ischemia and ischemic preconditioning in hippocampal neuron in gerbils / 中国应用生理学杂志

<p><b>AIM</b>To investigate the role of extracellular-signal regulated kinase (ERK) cascade on cerebral ischemia and ischemic preconditioning in hippocampal neuron.</p><p><b>METHODS</b>Male gerbils were randomly divided into sham group (SH), ischemia/reperfusion group (I/ R), ischemia preconditioning group (IP), specific antagonist of ERK-PD98059 (PD), solvent control groups (VE group), PD98059 combined with IP group (PIP). Forebrain ischemia was induced by occlusion of bilateral common carotid arteries and confirmed by isoelectricity of EEG. Observations were carried out in each group 15 min, 2 h, 4 h, 6 h, 1 d, 3 d, 5 d and 7 d after ischemia. Open field test was used to examine the spontaneous motor activity, the survival and apoptotic neurons, Fos and NF-kappaB masculine neurons in hippocampal CA1 region were counted, the expression of HSP70 in hippocampal CA1 region and p-ERK in hippocampal CA3/DG regions were detected by SABC immunocytochemical technique.</p><p><b>RESULTS</b>The spontaneous motor activity, the number of apoptotic neurons and NF-kappaB masculine neurons at 1 d, 3 d, 5 d, 7 d in CA1 region were much less in IP group than in I/R group (P < 0.01). The number of Fos masculine neurons at 15 min, 2 h, 4 h, 6 h, 1 d in CA1 region were significant more in IP group than in I/R group (P < 0.01). The expressions of p-ERK and HSP70 were significantly higher in IP group than in I/R group. The number of Fos masculine neurons at each point were more and apoptotic neurons at 1 d, 3 d were less in PD group than in I/R group. Results of observation in PIP group were within IP group and I/R group.</p><p><b>CONCLUSION</b>Activation of ERK in CA3/DG regions were related to ischemic tolerance. Induction of the expression of Fos and HSP70, decreasing of the product of NF-kB which might be one of the molecule mechanisms playing an important role in neural protection of ischemic preconditioning.</p>

Expression of drebrin in the distal cerebrospinal fluid contacting neurons of rats with chronic constriction injury of sciatic nerve / 生理学报

To observe the expression of drebrin in the distal cerebrospinal fluid contacting neurons (dCSF-CNs) of rats with chronic constriction injury (CCI) of sciatic nerve by immunofluorescence technique, male Sprague-Dawley rats were randomly divided into three groups: control group, sham surgery group and CCI group. The behavior of rats was scored. After choleratoxin subunit B-conjugated horseradish peroxidase (CB-HRP, 3 muL) was injected into the lateral cerebroventricle to trace dCSF-CNs, the expression of drebrin was observed in the dCSF-CNs through immunofluorescence double staining and laser scanning confocal microscopy technique. The results showed that only the pain threshold of CCI group was decreased. The dCSF-CNs were clearly displayed in three groups. No drebrin expression was observed in the control and sham groups. In CCI group, drebrin was markedly expressed in intracytoplasm. It is suggested that the technique displaying dCSF-CNs with immunofluorescence is successful and the dCSF-CNs are possibly involved in the transmission of nociceptive information under the neuropathic pain state.

Protective effect of heme oxygenase-1 on lung injury induced by erythrocyte instillation in rats / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Intratracheal instillation of blood induces self-repaired acute lung injury. However, the mechanism of repair has been unclear. Heme-oxygenase (HO)-1, which catalyzes heme breakdown, acts as an inducible defense against oxidative stress and plays an important role in inflammation. The objective of this study was to test the role of HO-1 in lung injury caused by intratracheal instillation of red cells.</p><p><b>METHODS</b>Forty healthy, male Sprague-Dawley rats were randomly divided into five groups: normal group, saline group, erythrocyte group, erythrocyte+zinc-protoporphyrin (ZnPP, HO-1 inhibitor) group and saline+ZnPP group. At 2 days after intratracheal instillation of red cells, lung tissues and lavage samples were isolated for biochemical determinations and histological measurements.</p><p><b>RESULTS</b>Histological analysis revealed that administration of ZnPP worsened the acute lung injury induced by instilled erythrocytes. HO-1 was over-expressed in the erythrocyte group and in the erythrocyte + ZnPP group. Compared with the erythrocyte + ZnPP group, the levels of total protein, lactate dehydrogenase and tumor necrosis factor-alpha in the lavage were lower (P < 0.01), while the level of interleukin-10 was higher in the erythrocyte group (P < 0.01).</p><p><b>CONCLUSION</b>HO-1 protects against erythrocyte-induced inflammatory injury in lung.</p>

Peripheral benzodiazepine receptor agonist Ro5-4864 inhibits mitochondrial permeability transition in rat heart / 生理学报

Opening of mitochondrial permeability transition (MPT) pores leads to mitochondrial injury during oxidative stress. The peripheral benzodiazepine receptor (PBR) located at mitochondrial outer-membrane has been shown to be involved in several mitochondrial functions. In the present study, we used Ro5-4864, a PBR agonist, to test if activation of PBR could prevent MPT pore opening during Ca(2+) overloading. Cardiac mitochondria isolated from Sprague-Dawley rats were treated by 150 mmol/L Ca(2+) to induce MPT. Ro5-4864 (50, 100 and 200 micromol/L) was added into incubation buffer before adding 150 micromol/L Ca(2+). In additional group, atractyloside (ATR, 20 micromol/L), an opener of MPT pores was added 5 min before the addition of 100 micromol/L Ro5-4864. The change of absorbance at 520 nm was monitored with a spectrophotometer at 30 degrees C for 10 min. Western blot was used to detect cytochrome C loss. The mitochondrial membrane potential was monitored with the fluorescence dye JC-1. Ro5-4864 inhibited the decrease of absorbance at 520 nm compared to that in the untreated Ca(2+) group (P<0.01, P<0.05). In the presence of ATR, Ro5-4864 was not able to prevent MPT anymore. Opening of MPT pores by Ca(2+) decreased the content of cytochrome C in mitochondria, but increased cytochrome C content in cytosol. Ro5-4864 preserved cytochrome C content in mitochondria and led to less cytochrome C release to cytosol. ATR treatment reversed the protective effect of Ro5-4864 on cytochrome C content. Opening of MPT pores led to mitochondrial depolarization, whereas Ro5-4864 treatment maintained mitochondrial membrane potential. Thus, prevention of MPT by activation of PBR during calcium overloading maintains mitochondrial cytochrome C content and membrane potential. Activation of PBR during cardiac ischemia and reperfusion may be an alternative way for cardioprotection.

The relationship between the effects of curcumin on cerebral ischemia/reperfusion injury and immediately genic expressions of fos, Jun and NF-kappaB in hippocampal CA1 area and its significance in gerbils / 中国应用生理学杂志

<p><b>AIM</b>To explore the relationship between the effects of curcumin on cerebral ischemic/reperfusion injury and immediately genic expressions of Fos, Jun and NF-kappaB in hippocampal CA1 area.</p><p><b>METHODS</b>Gerbils were randomly divided into sham group (SH), ischemia/reperfusion group (I/R), curcumin group (CU) and solvent control group (SC). Forebrain ischemia was induced by occlusion of bilateral common carotid arteries. Observations were carried out in each group 15 min, 1 h, 2 h, 6 h, 1 d, 3 d, 5 d and 7 d after ischemia: open field test was used to examine the behavioral change, the apoptosis neurons in hippocampal CA1 region was counted, the expression of Fos, Jun and NF-kappaB in hippocampal CA1 was detected by SABC immunocytochemical technique.</p><p><b>RESULTS</b>The behavioral mark and the number of apoptosis neurons in hippocampal (CA1 region was much less in CU group than in I/R group (P < 0.01) The expression of Fos was more and the expression of Jun and NF-kappaB was less in CA1 area in CU group than in I/R group (P < 0.01).</p><p><b>CONCLUSION</b>Curcumin can significantly protect neurons against cerebral ischemia, increasing the expression Fos and decreasing the expression of Jun and NF-kappaB may be the protective mechanisms.</p>

The lesion of CSF contacting neurons in rat brain parenchyma inhibits the development of morphine dependence and withdrawal / 中国应用生理学杂志

<p><b>AIM</b>To investigate the effect of CSF contacting neurons (CSF-CNs) lesion in rat dorsal raphe nucleus (DRN) on the scores of morphine withdrawal symptoms precipitated by naloxone and the nNOS expression in dorsal horn of spinal cord, and study the relationship between the distal CSF-CNs in rat brain parenchyma and the development of morphine dependence and withdrawal.</p><p><b>METHODS</b>Chemical lesion of neurons the injection of cholera toxin subunit B with horseradish peroxidase (CB-HRP) into one of the rats lateral ventricles, TMBST reaction, nNOS immunohistochemistry and Western blot were used in this study.</p><p><b>RESULTS</b>The withdrawal symptoms by the naloxone precipitated attenuated obviously after the lesion of CSF-CNs in rat DRN, scores of all signs were significantly decreased about 38% compared to that of withdrawal group without lesion (P < 0.05). The withdrawal symptoms scores of vehicle withdrawal group and side lesion withdrawal group were not changed significantly (P > 0.05). Neurons in the location of CSF-CNs concentrated in the rat brain slices of lesion group were damaged obviously, there were only few CB-HRP positive neurons around the lesion location. But the location and the quantity of the CB-HRP positive neurons in the brain slices of the group without lesion was stable relatively, and their appearance was very clear. After the lesion, the nNOS expression and the quantity of the nNOS positive neurons in dorsal horn of spinal cord decreased significantly compared to that of withdrawal group without lesion (P < 0.05), but it also increased significantly compared to that of normal group and dependence group (P < 0.01).</p><p><b>CONCLUSION</b>The lesion of distal CSF contacting neurons attenuated the scores of morphine withdrawal symptoms precipitated by naloxone and the nNOS expression in dorsal horn of spinal cord. The distal CSF contacting neurons in rat brain parenchyma partly participated in the development of morphine dependence and naloxone precipitated withdrawal possibly by the modulation of NO (nitric oxide).</p>

Distribution and expression of p38 MAPK in the distal cerebrospinal fluid contacting neurons in brain of rat by noise stress / 中国应用生理学杂志

<p><b>AIM</b>To observe the distribution and expression of p-p38MAPK in the distal cerebrospinal fluid contacting neurons in brain of rat by noise stress.</p><p><b>METHODS</b>By a double-labelled method combing the tracing of CB-HRP and the immunohistochemical technique p-p38MAPK, the distribution and expression of p-p38MAPK in the distal cerebrospinal fluid contacting neurons(csf cn) were observed following noise stress. Expression of p-p38MAPK and double-labelled of CB-HRP/p-p38MAPK were also observed in rat brain after noise stress.</p><p><b>RESULTS</b>Two groups of CB-HRP labeled neuron clusters consistently appeared in certain regions of the brainstem but none in other regions of the brain. Without noise stress exposure, only a few neurons were found double-labeled by CB-HRP/p-p38MAPK. After 1 day noise stress exposure, only few neurons double-labeled by CB-HRP/p-p38MAPK were observed in the above-mentioned regions. After 5 days, the number of neurons double-labeled by CB-HRP/p-p38MAPK increased significantly compared with the control group (P < 0.05). After 10 days, the number of neurons double-labeled by CB-HRP/p-p38MAPK increased significantly compared with the control group (P < 0.05). After 20 days, both of the numbers of neurons double-labeled by CB-HRP/p-p38MAPK increased significantly compared with that of the control group (P < 0.01).</p><p><b>CONCLUSION</b>Two groups of distal cerebrospinal fluid contacting neuron clusters consistently existed in certain regions of the brain parenchyma, and in these clusters only a few neurons con rained p-p38MAPK. After noise stress exposure of different durations (days 1, 5, 10, 20), the number of distal cerebrospinal fluid contacting neurons with p-p38MAPK increased significantly with increasing days. The results indicate that distal cerebrospinal fluid contacting neurons are special neurons existing consistently in brain, including distal cerebrospinal fluid contacting neurons with p-p38MAPK which may participate in the whole procedure of signal transduction or central modulation in noise stress response and play greater roles with increasing days.</p>

Effects of two fluid resuscitations on the bacterial translocation and inflammatory response of small intestine in rats with hemorrhagic shock / 中华创伤杂志(英文版)

<p><b>OBJECTIVE</b>To investigate the effects of two fluid resuscitations on the bacterial translocation and the inflammatory factors of small intestine in rats with hemorrhagic shock.</p><p><b>METHODS</b>Fifty SD healthy male rats were randomly divided into 5 groups (n equal to 10 per group): Group A (Sham group), Group B (Ringer's solution for 1 h), Group C (Ringer's solution for 24 h), Group D (hydroxyethyl starch for 1 h) and Group E ((hydroxyethyl starch for 24 h). A model of rats with hemorrhagic shock was established. The bacterial translocation in liver, content of tumor necrosis factor-alpha (TNF-alpha) and changes of myeloperoxidase enzyme (MPO) activities in small intestine were pathologically investigated after these two fluid resuscitations, respectively.</p><p><b>RESULTS</b>The bacterial translocation and the expression of TNF-alpha in the small intestine were detected at 1 h and 24 h after fluid resuscitation. There were significant increase in the number of translocated bacteria, TNF-alpha and MPO activities in Group C compared with Group B, significant decrease in Group E compared with Group D and in Group B compared with Group D. The number of translocated bacteria and TNF-alpha expression significantly decreased in Group E as compared with Group C.</p><p><b>CONCLUSIONS</b>The bacterial translocation and the expression of TNF-alpha in the small intestine exist 24 h after fluid resuscitation. 6% hydroxyethyl starch can improve the intestinal mucosa barrier function better than the Ringer's solution.</p>

Activation of ERK1/2 in spinal cord contributes to the development of acute cystic pain in rabbits / 神经科学通报·英文版

Objective To investigate the role of activated extracellular signal-regulated kinase 1/2 (ERK1/2) in spinal cord in the development of cystic pain in rabbit. Methods We observed the relationship between the activation of ERK1/2 in spinal cord and nociceptive behaviors, as well as the effect of U0126, a mitogen-activated protein kinase (MEK, upstream protein of ERK1/2) inhibitor, on cystic pain in rabbits by behavioral test, immunohistochemistry and western blot analysis. Results After injecting 0.5 ml formalin into gallbladder, the behaviors such as grasping of the cheek and licking of the abdomen increased in 30 min, with a significant increase in pERK1/2 expression in the spinal cord, as well as the pERK1/2 immunoreactive cells located in laminae V-VII and X of the dorsal horn and ventral horn of T6 spinal cord. Administration of U0126 (100 - 400 mu g/kg body weight, i.v., 10 min before instillation of formalin) could attenuated nociceptive behaviors dose-dependently, but could not restrain the nociceptive behaviors completely even at the maximal efficient dose of 400 mu g/kg body weight. Conclusion Activated ERK1/2 in the spinal cord at least partly participates in the development of acute inflammatory cystic pain induced by formalin in rabbits.

Protective effect of sevoflurane preconditioning on oxygen-glucose deprivation injury in rat hippocampal slices: the role of mitochondrial K(ATP) channels / 生理学报

To investigate the neuroprotective effects of sevoflurane preconditioning on oxygen-glucose deprivation (OGD) injury and the role of mitochondrial KATP channels in rat, we established OGD injury model in rat hippocampal slices. The brain was rapidly removed, and the dissected hippocampus was sliced in cold artificial cerebrospinal fluid (ACSF) transversely to its longitudinal axis (400 mum thick) with a Rotorslicer DTY-7700. Slices were placed on a nylon mesh in a recording chamber at 34 degrees C and humidified gas mixture (95% O2/5% CO2) was applied to the chamber at a flow rate of 200 ml/min. After 2 h of incubation, slices were randomly exposed to 2%, 4%, 6% sevoflurane or 6% sevoflurane combined with mitochondrial K(ATP) channel blocker (5-hydroxydecanoic acid, 5-HD) under normal condition (95% O2/5% CO2) for 30 min. Fifteen minutes later, slices were exposed to 14-minute OGD followed by 1-hour reoxygenation, and the changes of orthodromic population spike (OPS) at the end of reoxygenation were measured. The changes of ultrastructure of CA1 area in the group of 14-minute OGD followed by 1-hour reoxygenation were detected with electron microscope. The results showed that sevoflurane preconditioning delayed the abolishing time of OPS (P<0.01) and significantly increased the recovery rate and the recovery amplitude of OPS compared with the OGD group. The recovery rate of OPS was 71.4% both in 4% and 6% sevoflurane preconditioning groups (P<0.05 vs OGD group), accordingly the recovery amplitude of OPS was (61.0 +/- 42.3)% and (78.7 +/- 21.1)% (P<0.01), respectively. The protective effect of 6% sevoflurane was blocked by 5-HD. Ultrastructural observation in the hippocampal CA1 region of the OGD group showed severe edema of the pyramidal cells, crimpled or ruptured nucleus membranes, aggregation of chromatin, and swelling of mitochondria, whereas these changes were less prominent in 4% and 6% sevoflurane groups. These results suggest that sevoflurane preconditioning is capable to protect neurons from OGD injury in vitro and that the protective effect is related to the activation of mitochondrial K(ATP) channels.

The effects of diazoxide on myocardium function and the expressions of ERK and JNK in isolated spontaneous hypertension rat hearts / 中国应用生理学杂志

<p><b>AIM</b>To investigate the effect of diazoxide preconditioning and the role of ERK and JNK in cellular signaling during diazoxide preconditioning protection in isolated spontaneous hypertension rat (SHR) hearts.</p><p><b>METHODS</b>Hearts were isolated from male SHR rats, and perfused on a Langendorff apparatus. Five groups were considered (n = 6). Con: after 40 min perfusion the hearts were submitted to 25 min ischemia followed by 30 min reperfusion. IP: the hearts were preconditioned with 2 periods of 5 min ischemia and 10 min reperfusion prior to 25 min ischemia. DP: the hearts were preconditioned with 2 periods of 10 min K-H solution with 50 micromol x L(-1) diazoxide and 5 min K-H solution reperfusion prior to 25 min ischemia. 5-HD: perfuse with 100 micromol x L(-1) 5-HD (a special mitochondrial ATP sensitive potassium channel blocker) for 10 min followed by 30 min K-H solution perfusion before 25 min ischemia. 5-HD + DP: 100 micromol x L(-1) 5-HD was given for 10 min before diazoxide preconditioning.</p><p><b>RESULTS</b>During reperfusion, comparing with Con group, the recoveries of left ventricle developed pressure (LVDP), + dP/dt(max), - dP/dt(max) and left ventricle end diastolic pressure (LVEDP) were improved in IP and DP groups (P < 0.01 vs Con). At the end of reperfusion, compared with Con group, the expression of ERK in myocardium were higher in IP and DP groups (P < 0.01 vs Con), there was no significance between 5-HD and Con group, but 5-HD couldn't inhibit the expression of ERK induced by diazoxide preconditioning. The expression of JNK in IP and DP groups were decreased (P < 0.05 vs Con), this effect could been inhibited by 5-HD.</p><p><b>CONCLUSION</b>These results indicated that diazoxide preconditioning could mimic ischemic preconditioning, the activation of ERK expression and the declining of JNK expression involved in diazoxide preconditioning in isolated SHR hearts.</p>

Protective effects of propofol preconditioning on myocardium against hypothermia ischemia normothermia reperfusion injury on isolated rat hearts / 上海第二医科大学学报

Objective To investigate the protective effects of propofol preconditioning on myocardium against hypothermia ischemia normothermia reperfusion injury on isolated rat hearts. Methods The Langendorff apparatus was used.Sixty SD rat hearts were divided randomly into 5 groups after 20-minute equilibrium(n=12): control(Con) group,hearts were continually perfused with K-H buffer for 175 min;ischemia/reperfusion(I/R) group,hearts were perfused with K-H buffer for 40 min,then subjected to global ischemia at 27 ℃ for 75 min,and followed reperfusion at 37 ℃ for 60 min;propofol preconditioning group 1(P1),group 2(P2),and group 3(P3),hearts were perfused with K-H buffer including 50,100,and 150 ?mol/L propofol for 10 min and followed reperfusion like I/R group,respectively.Heart rate(HR),left ventricular end-diastolic pressure(LVEDP), left ventricular developed pressure(LVDP) and ?dp/dtmax at the end of equilibration,pre-ischemia and at the end of reperfusion were recorded.The contents of creatine kinase(CK) and lactate dehydrogenase(LDH) in coronary effluent were measured at the end of equilibration and 1,10,20,30,and 60 min during reperfusion.The activity of superoxide dismutase(SOD) and the contents of maleic dialdehyde(MDA) were measured at the end of reperfusion.The area of infarct region was determined at the end of reperfusion. Results HR,LVDP,?dp/dtmax and SOD activity in P2 and P3 group were higher than those in I/R group(P

Relation between GLu-R and the protective effect of hypothermia on oxygen and glucose deprivation injury in hippocampal slice or rat / 中国应用生理学杂志

<p><b>AIM</b>To investigate the relation between Glu-R and the protective effect of hypothermia on oxygen and glucose deprivation (OGD) injury in hippocampal slices of rat.</p><p><b>METHODS</b>(1) We had established OGD injury model in rat hippocampal slices. The changes of orthodromic population spike(OPS) during OGD and after administration of hypothermia (32 degrees C, 25 degrees C) were observed. (2) We had established Glu excitatory toxicity injury model in rat hippocampal slices. The changes of OPS after exposure to Glu and the effect of hypothermia (32 degrees C, 25 degrees C) against the Glu excitatory toxicity injury were observed. The non-NMDA receptor-mediated excitatory postsynaptic potentials (EPSP) in the CA1 area were recorded via adding the GABA-R specific agonists bicuculline (BMI) and NMDAR agonists D-(-)-2-Amino-5-phosphonopentanoic Acid (AP5) in normal artificial cerebrospinal fluid (nACSF), the NMDA receptor-mediated EPSP were recorded via adding the BMI and non-NMDA-R agonists 6,7-Dinitroquinoxaline-2, 3(1H,4H)-dione(CNQX) in nACSF. The variety of the changes of OPS during OGD14min in nACSF groups and added BMI compounded AP5 or BMI compounded CNQX ACSF groups were observed after administration of 25 degrees C hypothermia 28 min. (3) The changes of ultrastructure of CA1 area after OGD 1 h and the effect of hypothermia (25 degrees C) on it were observed.</p><p><b>RESULTS</b>(1) OPS reduced and abolished quickly during OGD14min, and the recovery amplitude of OPS was very low after reoxygenation/glucose 1 h. While the time of OPS abolishing significantly elongated and the recovery of OPS was higher in hypothermia (32 degrees, 25 degrees C) groups. The effect in groups 25 degrees C was more significant than those in groups 32 degrees C. (2) In control groups, Glu (2 mmol/L, 14 min) decreased the amplitude of OPS, after the end of Glu exposure the recovery amplitude of OPS was very low. After administration of hypothermia (32 degrees C, 25 degrees C), the recovery amplitude and rate of OPS were significantly higher than those in the control groups, while the antagonism on Glu excitatory toxicity injury in H 25 degrees C was more significant than those in H 32 degrees C. The changes of OPS during OGD 14 min were no distinct difference in nACSF groups and added BMI (50 micromol/L) compounded AP5(20 micromol/L) or BMI (50 micromol/L) compounded CNQX (100 micromol/L) ACSF groups. The protection of hypothermia (25 degrees C) could not be cancelled by added AP5 compounded BMI or BMI compounded CNQX in nACSF. (3) After OGD (14 min) 1 h, the nuclear membrane of pyramidal cells in CA1 area was irregular, nucleus were homogenized, the organelle in the cytoplasm was degenerate, even more to necrosis or loss, mitochondrion swelled, ridge was vacuoles. In H 25 degrees C the nuclear membrane was regular, mitochondrion swelled only lightly. Small chromatin gathered to edge.</p><p><b>CONCLUSION</b>Hypothermia shows the protective effects of against OGD injury in hippocampal slices. The mechanism is related to the antagonism of Glu excitor toxicity and maintenance the ATP level in cells, and the antagonism perhaps is mediated by NMDA-R and non-NMDA-R.</p>

cAMP response-element binding protein participates in the phosphorylated extracellular signal-regulate kinase mediated neuropathic pain / 生理学报

It has been reported that extracellular signal-regulate kinase (ERK) is involved in the modulation of nociceptive information and central sensitization produced by intense noxious stimuli and/or peripheral tissue inflammation. Few studies have explored the relationship between ERK and cAMP response-element binding protein (CREB) in neuropathic pain after nerve injury, such as chronic constriction injury (CCI) of the sciatic nerve. In the present study, CCI model was employed to investigate the activation of ERK on the expression of phosphorylated CREB (pCREB) in chronic neuropathic pain. Lumbar intrathecal catheters were chronically implanted in male Sprague-Dawley rats. The left sciatic nerve was loosely ligated proximal to the sciatica's trifurcation at around 1.0- mm intervals with 4-0 silk suture. Mitogen-activated protein kinase kinase (MEK) inhibitor U0126 and phosphorothioate-modified antisense oligonucleotides (ODN) were intrathecally administered one day before and three consecutive days after CCI. Thermal and mechanical nociceptive thresholds were assessed with the paw withdrawal lantency (PWL) to radiant heat and von Frey filaments respectively. The expression of pCREB and Fos were assessed by both Western blot and immunohistochemical analysis. The results showed that intrathecal injection of U0126 or ERK antisense ODN attenuated significantly CCI-induced mechanical and thermal hyperalgesia. Correlating with behavior results, the injection also markedly suppressed the increase of CCI-induced pCREB and c-Fos expression. The results obtained suggest that CREB participates in the pERK-mediated neuropathic pain.

Different roles of the spinal protein kinase C alpha and gamma in morphine dependence and naloxone-precipitated withdrawal / 生理学报

Our previous studies showed that spinal neurons sensitization was involved in morphine withdrawal response. This study was to investigate the roles of spinal protein kinase C (PKC) alpha, gamma in morphine dependence and naloxone-precipitated withdrawal response. To set up morphine dependence model, rats were subcutaneously injected with morphine (twice a day, for 5 d). The dose of morphine was 10 mg/kg in the first day and was increased by 10 mg/kg each day. On day 6, 4 h after the injection of morphine (50 mg/kg), morphine withdrawal syndrome was precipitated by an injection of naloxone (4 mg/kg, i.p.). Chelerythrine chloride (CHE), a PKC inhibitor, was intrathecally injected 30 min before the administration of naloxone. The scores of morphine withdrawal symptom and morphine withdrawal-induced allodynia were observed. One hour after naloxone-precipitated withdrawal, Fos protein expression was assessed by immunohistochemical analysis and Western blot was used to detect the expression of cytosol and membrane fraction of PKC alpha and gamma in the rat spinal cord. The results showed that intrathecal administration of CHE decreased the scores of morphine withdrawal, attenuated morphine withdrawal-induced allodynia and also inhibited the increase of Fos protein expression in the spinal cord of morphine withdrawal rats. The expression of cytosol and membrane fraction of PKC alpha was significantly increased in the spinal cord of rats with morphine dependence. Naloxone-precipitated withdrawal induced PKC alpha translocation from cytosol to membrane fraction, which was prevented by intrathecal administration of CHE. During morphine dependence, but not naloxone-precipitated withdrawal, PKC gamma in the spinal cord translocated from cytosol to membrane fraction, and intrathecal administration of CHE did not change the expression of PKC gamma in the spinal cord of naloxone-precipitated withdrawal rats. It is suggested that up-regulation and translocation of PKC in the spinal cord contribute to morphine dependence and naloxone-precipitated withdrawal in rats and that PKC alpha and gamma play different roles in the above-mentioned effect.

Inhibition of thermal hyperalgesia and tactile allodynia by intrathecal administration of gamma-aminobutyric acid transporter-1 inhibitor NO-711 in rats with chronic constriction injury / 生理学报

The present study was undertaken to explore the role of gamma-aminobutyric acid transporters in the neuropathic pain. On the chronic constriction injury (CCI) rats 4 doses (5, 10, 20, 40 microg in group N5, N10, N20, N40, respectively) of specific gamma-aminobutyric acid transporter-1 inhibitor NO-711 or normal saline (in group NS) were intrathecally administered before sciatic nerve ligation (pre-treatment) or at the third day after ligation (post-treatment). The paw withdrawl latency (PWL) from a noxious thermal stimulus and paw withdrawl mechanical threshold (PWMT) of von Frey filament was used as measure of thermal hyperalgesia and tactile allodynia respectively. The results demonstrated that post-treatment of NO-711 significantly suppressed thermal hyperalgesia and allodynia in CCI rats (P<0.05, P<0.01), the inhibitory effect lasted for 2 h (N40 group) and 4 h (N20 group) respectively. NO-711 inhibited thermal hyperalgesia induced by CCI in a dose-dependent manner. Intrathecal pretreatment with different doses of NO-711 delayed the occurrence of thermal hyperalgesia, but could not delay the emergence of allodynia induced by CCI. This study indicates that gamma-aminobutyric acid transporter inhibitor has anti-thermal hyperalgesia and anti-tactile allodynia effects in neuropathic rats.

Activation of p38 mitogen-activated protein kinase in spinal cord contributes to chronic constriction injury-induced neuropathic pain / 生理学报

The present study aimed to investigate the role of spinal p38 mitogen-activated protein kinase (p38 MAPK) activation in chronic constriction injury (CCI) of the sciatic nerve induced neuropathic pain. CCI model was produced by loosely ligating the left sciatic nerve proximal to the sciatica's trifurcation with 4-0 silk thread in male Sprague-Dawley rat. SB203580, a specific inhibitor of the p38 MAPK, was intrathecally administered on day 5 post-CCI. Thermal and mechanical nociceptive thresholds were assessed with the paw withdrawal lantency (PWL) to radiant heat and the paw withdrawal threshold (PWT) to von Frey filaments respectively. The protein levels of the phosphorylated p38 MAPK (p-p38 MAPK) and phosphorylated cAMP response element binding protein (pCREB) were assessed by Western blot analysis. The results showed that CCI significantly increased the expressions of cytosolic and nuclear p-p38 MAPK in the spinal cord. Intrathecal administration of SB203580 dose-dependently reversed the established mechanical allodynia and thermal hyperalgesia induced by CCI. Correlated with behavior results, SB203580 dose-dependently inhibited the CCI-induced increase of the expressions of cytosolic and nuclear p-p38 MAPK and nuclear pCREB in the spinal cord. Taken together, these findings suggest that the activation of p38 MAPK pathway contributes to the development of neuropathic pain induced by CCI, and that the function of p-p38 MAPK may partly be accomplished via the CREB-dependent gene expression.