The effect of Pb2+ on 3H-DL-Glutamate (3H-DL-Glu) binding in the membrane preparations from the hippocampus of rat brain was investigated with a view to explaining the cognitive and learning deficits produced by the h...The effect of Pb2+ on 3H-DL-Glutamate (3H-DL-Glu) binding in the membrane preparations from the hippocampus of rat brain was investigated with a view to explaining the cognitive and learning deficits produced by the heavy metal. The results indicated that Pb2+ (3. 1-25. 0 μmol.L -1 ) inhibited 3 H-DL-Glu binding in a concentration-dependent manner . Scatchard analysis further revealed that at a concentration of 6. 3 μmol.L-1 Pb2 + interfered with binding mainly through significantly decreasing the density of binding sites. This finding provided an important insight into Pb2+ -induced impairments in learning and memory previously documented in children and in experimental animals chronically exposed to Pb^(2+)展开更多
BACKGROUND： Some studies suggest that the long-term potentiation （LTP） of synaptic transmission may be the basis for the neural synaptic plasticity of hippocampus, but can be evoked by various factors including ele...BACKGROUND： Some studies suggest that the long-term potentiation （LTP） of synaptic transmission may be the basis for the neural synaptic plasticity of hippocampus, but can be evoked by various factors including electroacupuncture. OBJECTIVE： To observe the effect of electroacupuncture on the activities of basic synaptic transmission in dentate gyrus of hippocampus and the changes of high frequency stimulation （HFS） induced activity of synaptic transmission in cerebral ischemic injured rats. DESIGN： A randomized control trial.SETTING： Shenzhen Hospital of Traditional Chinese Medicine affiliated to Guangzhou University of Traditional Chinese Medicine. MATERIALS： Sixty healthy male Wistar rats, weighing 150-250 g, were provided by the Experimental Animal Center of Guangzhou University of Traditional Chinese Medicine. The experiment began after adaptation of environment for 1 week under standard experimental environment. The main experimental instruments included the programming electrical acupuncture apparatus （PCEA, product of the Institute of Acupuncture and Meridians, Anhui College of Traditional Chinese Medicine） and multichannel physiologic recorder （RM-86, Nihon Konden）. METHODS： The experiment was carried out in Guangzhou University of Traditional Chinese Medicine between July 2003 and July 2004. ①Embedding of brain electrodes： In reference of the Pellegrino＇s rat brain atlas, the bipolar electrode stimulator was embedded into the perforant path （PP） anterior to the entorhinal area with location coordinates of AP 7.5 mm, L 4.2 mm and H 3.0 mm, that is, 7.5 mm posterior to the anterior fontanelle, 4.2 mm laterally on the right side and 3.0 mm under the subcortex. The subcortex recorder electrode coordinates are AP 3.8 mm, L 2.5 mm and H 3.5 mm, located in the granular cell layer of the unilateral dentate gyrus （DG） of hippocampus, at the site of which an opening with the diameter of 1.5 mm was drilled for the purpose of embedding of the stimulating and recording electrodes, and at the site by mild adjusting the positions of these electrodes where maximal population spike （PS） was recorded, fastened the electrodes at last. ② The 60 rats were randomized into two major groups, namely, fundamental stimulation （FS） group （basic group） and high frequency stimulation （HFS） group. Each group was further divided into three subgroups respectively： Sham-operated subgroup （n=10）： only exposed bilateral common carotid arteries without blocking their blood flow; Cerebral ischemia model subgroup （n=10）： exposing bilateral common carotid arteries and blocking their blood flow; Ischemia plus electroacupuncture subgroup （n=10）： blocked blood flow of bilateral common carotid arteries and received electroacupuncture. The electroacupuncture acupoints were the points of Du meridian, including Baihui （GV20）, Dazhui （GV14）, and points of Pen meridian, including Qihai （CV6） and Guanyuan （CV4）. ③ Process of electroacupuncture： All the rats underwent testing stimulation （1/30 Hz frequency and 0.1 ms breadth） at 30 minutes before modeling, PS values were recorded as the indexes of the excitation of DG granular cell population, and the data were input to computer for data analysis. During the experiment, the intensity of stimulation was kept stable by adopting 1/2 the value of stimulation intensity that could induce maximal PS amplitude. In the basic group, PS were recorded for 120 minutes after modeling, and among the rats in the electroacupuncture group, PS was recorded at 10 minutes before and 60 minutes after blocking blood flow in the carotid artery during continuous electrical acupuncture. In the HFS group, HFS was given immediately after modeling, PS were recorded for 180 minutes at 10 minutes after HFS was given in the sham-operated group and model group, rats in the electroacupuncture group were treated with electroacupuncture for 60 minutes at 30 minutes after HFS was given, and PS was recorded for 180 minutes after 10 minutes. LTP was triggered by HFS and PS values were determined and recorded through measuring stimulations respectively 0, 10, 30, 60, 120 and 180 minutes after the evokes.④ Methods for expressing the level of synaptic transmission： Each testing stimulus provoked one PS, and 10 successive amplitude values （V/mV） were averaged relevant to a certain time cut. The averaged PS of 6 time cuts at 30 minutes before modeling was made as basal synaptic transmission level as control. Synaptic transmission at each time cut was expressed as： p=（ Vdifferentime cut / Vbasal） × 100%. MAIN OUTCOME MEASURES： The differences of synaptic transmission level were compared among the subgroups in the basic group after models also among the subgroups in the HFS group after HFS.RESULTS： All the 60 rats were involved in the analysis of results. ① Comparison of synaptic transmission level at different time cut after modeling and the effect of electroacupuncture in the subgroups of the basic group： The synaptic transmission level in the sham-operated subgroup had no significant change within 120 minutes （P 〉 0.05）. The synaptic transmission levels at 10, 30 and 60 minutes in the model subgroup were obviously lower than those in the sham-operated group [（60±7）%, （90±3）%, （93±4）%; （100±5）%, （102±6）%, （105±7）%, P 〈 0.05-0.01]. With the prolongation of time for ischemia/reperfusion, the synaptic transmission level gradually ascended to the normal level, and those at 90 and 120 minutes were close to those in the sham-operated group （P 〉 0.05）. In the subgroup of electroacupuncture, the synaptic transmission levels at 10, 30, 60, 90 and 120 minutes were obviously higher than those in the model subgroup [（93±5）%, （106±10）%, （123±16）%, （145±20）%, （168±25）%; （96±7）%, （98±8）%, P 〈 0.05-0.01].② Comparison of synaptic transmission level at different time cut after HFS and the effect of electroacupuncture in the groups： In the sham-operated group, the synaptic transmission level after HFS increased significantly, and maintained without decrease within 180 minutes. In the model group, the synaptic transmission level at 0, 10, 30, 60, 120 and 180 minutes after HFS were obviously lower than those in the sham-operated group [（60±7）%, （95±9）%, （138±11）%, （141±13）%, （140±13）%, （138±15）%; （100±6）%, （182±21）%, （179±18）%, （177±18）%, （175±23）%, （178±24）%, P 〈 0.01]. The synaptic transmission level at 60, 120 and 180 minutes after HFS in the electroacupuncture group were close to those in the sham-operated group （P 〉 0.05）, those at 120 and 180 minutes after HFS in the electroacupuncture group were obviously higher than those in the model group [（171±22）%, （181±25）%, P 〈 0.05-0.01]. CONCLUSION： Electroacupuncture could enhance the basic activity of synaptic transmission in the dentate gyros of hippocampus in cerebral ischemic injury in rats. Electroacupuncture has obvious LTP effect on the activity of synaptic transmission induced by HFS.展开更多
BACKGROUND： Prenatal stress has been shown to inhibit cell proliferation in the dentate gyrus and hippocampus, reduce hippocampal volume, and cause neuronal loss and oxidative damage in the hippocampus of offspring r...BACKGROUND： Prenatal stress has been shown to inhibit cell proliferation in the dentate gyrus and hippocampus, reduce hippocampal volume, and cause neuronal loss and oxidative damage in the hippocampus of offspring rats, but the sexual difference of the effects on offsprings is seldom referred to. OBJECTIVE： To observe the effect of prenatal stress to adult pregnant rats on expression of extracellular signal-regulated kinases （ERK） in hippocampus of the offspring rats of different genders. DESIGN ： A randomized and control animal experiment.SETTING： Department of Physiology and Pathophysiology, School of Medicine, Xi＇an Jiaotong University. MATERIALS ： The experiments were carried out in the Key Laboratory of Environment and Gene Related Diseases （Xi＇an Jiaotong University）, Ministry of Education between October 2005 and March 2006. Fifteen female and five male adult Sprague-Dawley rats were adopted. Female rats weighing 230-250 g and male rats weighing 280-350 g were used. METHODS： The virgin female rats were placed overnight with adult male rats （3：1） for mating. A total of twelve pregnant rats were randomly assigned to prenatal stress group （PNS group, n=6） and control group （n=6）. The pregnant rats of the PNS group were exposed to restraint stress on days 14-20 of pregnancy three times a day, 45 minutes for each time . The restraint device was a transparent plastic tube （6.8 cm in diameter） with air holes for breathing and closed end. The length could be adjusted to accommodate the size of the animals. To prevent habituation of animals to the daily procedure, restraint periods were randomly shifted within certain time periods （8：00-11：00, 11：00-14：00, and 16：00-19：00）. After birth, offsprings of all groups were culled to 8-10 litters in each group and housed in the same animal room, and kept together with their biologic mothers. The pregnant rats of the control group were left undisturbed. On day 21, after all the offspring were weaned, male and female pups were separated and housed four in each cage respectively until test at 30 days of age. At the end of postnatal day 30, one male and female offspring rats from the same dam were selected with a random choice and a total of 24 animals from 12 different dams were used. The experimental rats were sacrificed by decapitation under anesthesia. Bilateral hippocampal tissues were isolated and homogenized in cold condition. Alkaline carbonate buffer （BCA） method was used to detect the concentration of extracellular signal-regulated kinases （ERK）, then mixed with loading buffer, the constant voltage was 100 V. Finally, BCIP/NBT staining and electrDphoresis were performed, the absorbance （A） value for the bands was detected with the Bandscan analytical software, and the expression of ERK in hippocampus of offspring rats of different genders in each group was quantitatively analyzed. MAIN OUTCOME MEASURES： The level of ERK expression in hippocampus of offspring rats of different genders in each group was observed.RESULTS： All the 24 offspring rats were involved in the analysis of results. ① The staining results of ERP activity in the extract of brain tissue detected with Western blotting technique and specific antibody analysis showed that the ERP in hippocampus of offspring rats had two subtypes of ERK-1 and ERK-2, and the latter was the main type.② Standardized by the average A value in the control group, the quantitative data of the general A value of total ERK showed that the expression of ERK-2 in hippocampus of female offspring rats was obviously higher in the PNS group than in the control group （A value： 126±6.76,100±4.89,P〈 0.01）. ③The expression of ERK-2 had no obvious difference between the female and male offspring rats in the control group.④ The expression of ERK-2 in hippocampus of male offspring rats was a little higher in the PNS group than in the control group （A value： 104±6.27,102±5.48,P 〉 0.05）. CONCLUSION ： PNS significantly affects the increase of ERK expression in hippocampus of female offspring rats, but has no obvious influence on that of male ones.展开更多
文摘The effect of Pb2+ on 3H-DL-Glutamate (3H-DL-Glu) binding in the membrane preparations from the hippocampus of rat brain was investigated with a view to explaining the cognitive and learning deficits produced by the heavy metal. The results indicated that Pb2+ (3. 1-25. 0 μmol.L -1 ) inhibited 3 H-DL-Glu binding in a concentration-dependent manner . Scatchard analysis further revealed that at a concentration of 6. 3 μmol.L-1 Pb2 + interfered with binding mainly through significantly decreasing the density of binding sites. This finding provided an important insight into Pb2+ -induced impairments in learning and memory previously documented in children and in experimental animals chronically exposed to Pb^(2+)
文摘BACKGROUND： Some studies suggest that the long-term potentiation （LTP） of synaptic transmission may be the basis for the neural synaptic plasticity of hippocampus, but can be evoked by various factors including electroacupuncture. OBJECTIVE： To observe the effect of electroacupuncture on the activities of basic synaptic transmission in dentate gyrus of hippocampus and the changes of high frequency stimulation （HFS） induced activity of synaptic transmission in cerebral ischemic injured rats. DESIGN： A randomized control trial.SETTING： Shenzhen Hospital of Traditional Chinese Medicine affiliated to Guangzhou University of Traditional Chinese Medicine. MATERIALS： Sixty healthy male Wistar rats, weighing 150-250 g, were provided by the Experimental Animal Center of Guangzhou University of Traditional Chinese Medicine. The experiment began after adaptation of environment for 1 week under standard experimental environment. The main experimental instruments included the programming electrical acupuncture apparatus （PCEA, product of the Institute of Acupuncture and Meridians, Anhui College of Traditional Chinese Medicine） and multichannel physiologic recorder （RM-86, Nihon Konden）. METHODS： The experiment was carried out in Guangzhou University of Traditional Chinese Medicine between July 2003 and July 2004. ①Embedding of brain electrodes： In reference of the Pellegrino＇s rat brain atlas, the bipolar electrode stimulator was embedded into the perforant path （PP） anterior to the entorhinal area with location coordinates of AP 7.5 mm, L 4.2 mm and H 3.0 mm, that is, 7.5 mm posterior to the anterior fontanelle, 4.2 mm laterally on the right side and 3.0 mm under the subcortex. The subcortex recorder electrode coordinates are AP 3.8 mm, L 2.5 mm and H 3.5 mm, located in the granular cell layer of the unilateral dentate gyrus （DG） of hippocampus, at the site of which an opening with the diameter of 1.5 mm was drilled for the purpose of embedding of the stimulating and recording electrodes, and at the site by mild adjusting the positions of these electrodes where maximal population spike （PS） was recorded, fastened the electrodes at last. ② The 60 rats were randomized into two major groups, namely, fundamental stimulation （FS） group （basic group） and high frequency stimulation （HFS） group. Each group was further divided into three subgroups respectively： Sham-operated subgroup （n=10）： only exposed bilateral common carotid arteries without blocking their blood flow; Cerebral ischemia model subgroup （n=10）： exposing bilateral common carotid arteries and blocking their blood flow; Ischemia plus electroacupuncture subgroup （n=10）： blocked blood flow of bilateral common carotid arteries and received electroacupuncture. The electroacupuncture acupoints were the points of Du meridian, including Baihui （GV20）, Dazhui （GV14）, and points of Pen meridian, including Qihai （CV6） and Guanyuan （CV4）. ③ Process of electroacupuncture： All the rats underwent testing stimulation （1/30 Hz frequency and 0.1 ms breadth） at 30 minutes before modeling, PS values were recorded as the indexes of the excitation of DG granular cell population, and the data were input to computer for data analysis. During the experiment, the intensity of stimulation was kept stable by adopting 1/2 the value of stimulation intensity that could induce maximal PS amplitude. In the basic group, PS were recorded for 120 minutes after modeling, and among the rats in the electroacupuncture group, PS was recorded at 10 minutes before and 60 minutes after blocking blood flow in the carotid artery during continuous electrical acupuncture. In the HFS group, HFS was given immediately after modeling, PS were recorded for 180 minutes at 10 minutes after HFS was given in the sham-operated group and model group, rats in the electroacupuncture group were treated with electroacupuncture for 60 minutes at 30 minutes after HFS was given, and PS was recorded for 180 minutes after 10 minutes. LTP was triggered by HFS and PS values were determined and recorded through measuring stimulations respectively 0, 10, 30, 60, 120 and 180 minutes after the evokes.④ Methods for expressing the level of synaptic transmission： Each testing stimulus provoked one PS, and 10 successive amplitude values （V/mV） were averaged relevant to a certain time cut. The averaged PS of 6 time cuts at 30 minutes before modeling was made as basal synaptic transmission level as control. Synaptic transmission at each time cut was expressed as： p=（ Vdifferentime cut / Vbasal） × 100%. MAIN OUTCOME MEASURES： The differences of synaptic transmission level were compared among the subgroups in the basic group after models also among the subgroups in the HFS group after HFS.RESULTS： All the 60 rats were involved in the analysis of results. ① Comparison of synaptic transmission level at different time cut after modeling and the effect of electroacupuncture in the subgroups of the basic group： The synaptic transmission level in the sham-operated subgroup had no significant change within 120 minutes （P 〉 0.05）. The synaptic transmission levels at 10, 30 and 60 minutes in the model subgroup were obviously lower than those in the sham-operated group [（60±7）%, （90±3）%, （93±4）%; （100±5）%, （102±6）%, （105±7）%, P 〈 0.05-0.01]. With the prolongation of time for ischemia/reperfusion, the synaptic transmission level gradually ascended to the normal level, and those at 90 and 120 minutes were close to those in the sham-operated group （P 〉 0.05）. In the subgroup of electroacupuncture, the synaptic transmission levels at 10, 30, 60, 90 and 120 minutes were obviously higher than those in the model subgroup [（93±5）%, （106±10）%, （123±16）%, （145±20）%, （168±25）%; （96±7）%, （98±8）%, P 〈 0.05-0.01].② Comparison of synaptic transmission level at different time cut after HFS and the effect of electroacupuncture in the groups： In the sham-operated group, the synaptic transmission level after HFS increased significantly, and maintained without decrease within 180 minutes. In the model group, the synaptic transmission level at 0, 10, 30, 60, 120 and 180 minutes after HFS were obviously lower than those in the sham-operated group [（60±7）%, （95±9）%, （138±11）%, （141±13）%, （140±13）%, （138±15）%; （100±6）%, （182±21）%, （179±18）%, （177±18）%, （175±23）%, （178±24）%, P 〈 0.01]. The synaptic transmission level at 60, 120 and 180 minutes after HFS in the electroacupuncture group were close to those in the sham-operated group （P 〉 0.05）, those at 120 and 180 minutes after HFS in the electroacupuncture group were obviously higher than those in the model group [（171±22）%, （181±25）%, P 〈 0.05-0.01]. CONCLUSION： Electroacupuncture could enhance the basic activity of synaptic transmission in the dentate gyros of hippocampus in cerebral ischemic injury in rats. Electroacupuncture has obvious LTP effect on the activity of synaptic transmission induced by HFS.
基金the National Natural Science Foundation of China, No. 30270445
文摘BACKGROUND： Prenatal stress has been shown to inhibit cell proliferation in the dentate gyrus and hippocampus, reduce hippocampal volume, and cause neuronal loss and oxidative damage in the hippocampus of offspring rats, but the sexual difference of the effects on offsprings is seldom referred to. OBJECTIVE： To observe the effect of prenatal stress to adult pregnant rats on expression of extracellular signal-regulated kinases （ERK） in hippocampus of the offspring rats of different genders. DESIGN ： A randomized and control animal experiment.SETTING： Department of Physiology and Pathophysiology, School of Medicine, Xi＇an Jiaotong University. MATERIALS ： The experiments were carried out in the Key Laboratory of Environment and Gene Related Diseases （Xi＇an Jiaotong University）, Ministry of Education between October 2005 and March 2006. Fifteen female and five male adult Sprague-Dawley rats were adopted. Female rats weighing 230-250 g and male rats weighing 280-350 g were used. METHODS： The virgin female rats were placed overnight with adult male rats （3：1） for mating. A total of twelve pregnant rats were randomly assigned to prenatal stress group （PNS group, n=6） and control group （n=6）. The pregnant rats of the PNS group were exposed to restraint stress on days 14-20 of pregnancy three times a day, 45 minutes for each time . The restraint device was a transparent plastic tube （6.8 cm in diameter） with air holes for breathing and closed end. The length could be adjusted to accommodate the size of the animals. To prevent habituation of animals to the daily procedure, restraint periods were randomly shifted within certain time periods （8：00-11：00, 11：00-14：00, and 16：00-19：00）. After birth, offsprings of all groups were culled to 8-10 litters in each group and housed in the same animal room, and kept together with their biologic mothers. The pregnant rats of the control group were left undisturbed. On day 21, after all the offspring were weaned, male and female pups were separated and housed four in each cage respectively until test at 30 days of age. At the end of postnatal day 30, one male and female offspring rats from the same dam were selected with a random choice and a total of 24 animals from 12 different dams were used. The experimental rats were sacrificed by decapitation under anesthesia. Bilateral hippocampal tissues were isolated and homogenized in cold condition. Alkaline carbonate buffer （BCA） method was used to detect the concentration of extracellular signal-regulated kinases （ERK）, then mixed with loading buffer, the constant voltage was 100 V. Finally, BCIP/NBT staining and electrDphoresis were performed, the absorbance （A） value for the bands was detected with the Bandscan analytical software, and the expression of ERK in hippocampus of offspring rats of different genders in each group was quantitatively analyzed. MAIN OUTCOME MEASURES： The level of ERK expression in hippocampus of offspring rats of different genders in each group was observed.RESULTS： All the 24 offspring rats were involved in the analysis of results. ① The staining results of ERP activity in the extract of brain tissue detected with Western blotting technique and specific antibody analysis showed that the ERP in hippocampus of offspring rats had two subtypes of ERK-1 and ERK-2, and the latter was the main type.② Standardized by the average A value in the control group, the quantitative data of the general A value of total ERK showed that the expression of ERK-2 in hippocampus of female offspring rats was obviously higher in the PNS group than in the control group （A value： 126±6.76,100±4.89,P〈 0.01）. ③The expression of ERK-2 had no obvious difference between the female and male offspring rats in the control group.④ The expression of ERK-2 in hippocampus of male offspring rats was a little higher in the PNS group than in the control group （A value： 104±6.27,102±5.48,P 〉 0.05）. CONCLUSION ： PNS significantly affects the increase of ERK expression in hippocampus of female offspring rats, but has no obvious influence on that of male ones.
