Aim: To record the single-channel currents and characterize the electrophysiological properties of the Cl^- channels inhuman sperm membrane. Methods: The membrane proteins extracted from the human sperm were reassembl...Aim: To record the single-channel currents and characterize the electrophysiological properties of the Cl^- channels inhuman sperm membrane. Methods: The membrane proteins extracted from the human sperm were reassembled intoliposome bilayer, and the liposomes were fused into giant liposomes with a diameter more than 10μm by dehydration-rehydration procedure. The giant liposomes were used to study the Cl^- channel activities by patch-clamp technique.Results: By patch clamping the giant liposome in an asymmetric NMDG (N-methyl-D-glucamine)-Cl (bath 100//pipette 200 mmol/L) solution system, three kinds of single-channel events with unit conductances of (74.1 ± 8.3) pS,(117.0±5.7) pS and (144.7±4.5) pS, respectively, were detected. Their activities were voltage-dependent and allwere blocked by SITS (4-acetamido-4'-isothiocyanato-stilbene-2', 2'-disulfonic acid) in a concentration-dependentmanner. By constructing the open and close dwell time distribution histograms and then fitting them with exponentialfunction, two time constants were obtained in both the open and the close states. The burst activity and conductancesubstate of the channels were observed. Conclusion; There exist three kinds of Cl^- channels with different conduc-tance in human sperm membrane at least. (Asian J Androl 2001 Sep; 3: 185 - 191)展开更多
AIM： To induce the pancreatic duct cells into endocrine cells with a new natural protocol for electrophysiological study. METHODS： The pancreatic duct cells of neonatal rats were isolated, cultured and induced into ...AIM： To induce the pancreatic duct cells into endocrine cells with a new natural protocol for electrophysiological study. METHODS： The pancreatic duct cells of neonatal rats were isolated, cultured and induced into endocrine ceils with 15% fetal bovine serum for a period of 20 d. During this period, insulin secretion, MTT value, and morphological change of neonatal and adult pancreatic islet cells were comparatively investigated. Pancreatic β-cells were identified by morphological and electrophysiological characteristics, while ATP sensitive potassium channels （KATP）, voltage-dependent potassium channels （Kv）, and voltage-dependent calcium channels （KcA） in β-cells were identified by patch clamp technique. RESULTS： After incubation with fetal bovine serum, the neonatal duct cells budded out, changed from duct-like cells into islet clusters. In the first 4 d, MTT value and insulin secretion increased slowly （MTT value from 0.024 ±0.003 to 3.028±0.003, insulin secretion from 2.6±0.6 to 3.1±0.8 mIU/L）. Then MTT value and insulin secretion increased quickly from d 5 to d 10 （MTT value from 0.028 ±0.003 to 0.052±0.008, insulin secretion from 3.1±0.8 to 18.3±2.6 mIU/L）, then reached high plateau （MTT value 〉0.052±0.008, insulin secretion 〉18.3±2.6 mIU/L）. In contrast, for the isolated adult pancreatic islet cells, both insulin release and MTT value were stable in the first 4 d （MTT value from 0.029±0.01 to 0.031±0.011, insulin secretion from 13.9±3.1 to 14.3±3.3 mIU/L）, but afterwards they reduced gradually （MTT value 〈0.031 ±0.011, insulin secretion 〈8.2±1.5 mIU/L）, and the pancreatic islet cells became dispersed, broken or atrophied correspondingly. The differentiated neonatal cells were identified as pancreatic islet cells by dithizone staining method, and pancreatic β-cells were further identified by both morphological features and electrophysiological characteristics, i.e. the existence of recording currents from KATP, Kv, and KCA. CONCLUSION： Islet cells differentiated from neonatal pancreatic duct cells with the new natural protocol are more advantageous in performing patch clamp study over the isolated adult pancreatic islet cells.展开更多
The patch clamp recording technique in vivois a blind patch clamp recording methods to record the current of the spinal or cereral neurons of anaes：hesia （ or awake） animals. This technique can be used to study the...The patch clamp recording technique in vivois a blind patch clamp recording methods to record the current of the spinal or cereral neurons of anaes：hesia （ or awake） animals. This technique can be used to study the synaptic function and plasticity in central nervous system in vivoin order to understand the physiological properties of the ion channels from an integrated point of view. The advantage of this technique have already presented itself in the study of the synaptic transmission and nervous network. Nowadays, in vivo patch whole-cell recording technique in combination with other techniques is becoming a common method in the research fields.展开更多
We used whole-vacuolar patch-clamp recording mode to study the action mechanism of La3+ to Slow Vacuolar (SV) channels for the first time. We recorded SV channel currents of Xinlimei (Raphanus satirus L.) vacuolars. T...We used whole-vacuolar patch-clamp recording mode to study the action mechanism of La3+ to Slow Vacuolar (SV) channels for the first time. We recorded SV channel currents of Xinlimei (Raphanus satirus L.) vacuolars. The minimum activation potentials of voltage-dependent SV channels tied in 25+/-5 mV. The increase in cytoplasmic Ca2+ led to enhancement of SV-type currents. It was found that the threshold potential of activation shifted towards more depolarized values whenever cytoplasmic Ca2+ was increased. When 10(-10) mol/L free La3+ was added to the bath, SV-type current was suppressed by 60 similar to 75%. These data showed La3+ reduced ion permeabilities of Xinlimei root vacuolar membrane.展开更多
The single ion channel signal is an ionic current that can be recorded by the patch clamp technique. Hidden Markov model (HMM) algorithm has been used to convert the low signal noise ratio (SNR) noisy recording into a...The single ion channel signal is an ionic current that can be recorded by the patch clamp technique. Hidden Markov model (HMM) algorithm has been used to convert the low signal noise ratio (SNR) noisy recording into an idealized quantal one in the case of white background noise. The traditional HMM algorithm is extended and adapted to the colored background noise. A new algorithm called EHMM (Extended HMM) algorithm is proposed, and mainly validated by simulation. Results show that it’s effective.展开更多
One kind of novel BLMs was fabricated by patch-clamp pipette technology characterized in considerably sensitive to changes of electrochemical parameters.Detectiye currents and voltage presented linear relationship whe...One kind of novel BLMs was fabricated by patch-clamp pipette technology characterized in considerably sensitive to changes of electrochemical parameters.Detectiye currents and voltage presented linear relationship when BLMs was formed and it could be confirmed by Gramicidin method.Ion current was increased by dihexyl (C_ (12)) modified ssDNA fixed on the BLMs and also indicated linear relationship to ssDNA's concentration due to the interaction of (C_ 12)-ssDNA and BLMs.Further more,the regression equations were different from BLMs fixed with ssDNA probe and a blank control BLM in the same experimental conditions.The ssDNA probe was successfully fixed on patch-clamp pipette supported-BLMs.Based on our studies,a biosensor with reactive element of patch-clamp pipette-supported BLMs has been established.展开更多
文摘Aim: To record the single-channel currents and characterize the electrophysiological properties of the Cl^- channels inhuman sperm membrane. Methods: The membrane proteins extracted from the human sperm were reassembled intoliposome bilayer, and the liposomes were fused into giant liposomes with a diameter more than 10μm by dehydration-rehydration procedure. The giant liposomes were used to study the Cl^- channel activities by patch-clamp technique.Results: By patch clamping the giant liposome in an asymmetric NMDG (N-methyl-D-glucamine)-Cl (bath 100//pipette 200 mmol/L) solution system, three kinds of single-channel events with unit conductances of (74.1 ± 8.3) pS,(117.0±5.7) pS and (144.7±4.5) pS, respectively, were detected. Their activities were voltage-dependent and allwere blocked by SITS (4-acetamido-4'-isothiocyanato-stilbene-2', 2'-disulfonic acid) in a concentration-dependentmanner. By constructing the open and close dwell time distribution histograms and then fitting them with exponentialfunction, two time constants were obtained in both the open and the close states. The burst activity and conductancesubstate of the channels were observed. Conclusion; There exist three kinds of Cl^- channels with different conduc-tance in human sperm membrane at least. (Asian J Androl 2001 Sep; 3: 185 - 191)
基金Supported by the National Natural Science Foundation of China,No. 30472254
文摘AIM： To induce the pancreatic duct cells into endocrine cells with a new natural protocol for electrophysiological study. METHODS： The pancreatic duct cells of neonatal rats were isolated, cultured and induced into endocrine ceils with 15% fetal bovine serum for a period of 20 d. During this period, insulin secretion, MTT value, and morphological change of neonatal and adult pancreatic islet cells were comparatively investigated. Pancreatic β-cells were identified by morphological and electrophysiological characteristics, while ATP sensitive potassium channels （KATP）, voltage-dependent potassium channels （Kv）, and voltage-dependent calcium channels （KcA） in β-cells were identified by patch clamp technique. RESULTS： After incubation with fetal bovine serum, the neonatal duct cells budded out, changed from duct-like cells into islet clusters. In the first 4 d, MTT value and insulin secretion increased slowly （MTT value from 0.024 ±0.003 to 3.028±0.003, insulin secretion from 2.6±0.6 to 3.1±0.8 mIU/L）. Then MTT value and insulin secretion increased quickly from d 5 to d 10 （MTT value from 0.028 ±0.003 to 0.052±0.008, insulin secretion from 3.1±0.8 to 18.3±2.6 mIU/L）, then reached high plateau （MTT value 〉0.052±0.008, insulin secretion 〉18.3±2.6 mIU/L）. In contrast, for the isolated adult pancreatic islet cells, both insulin release and MTT value were stable in the first 4 d （MTT value from 0.029±0.01 to 0.031±0.011, insulin secretion from 13.9±3.1 to 14.3±3.3 mIU/L）, but afterwards they reduced gradually （MTT value 〈0.031 ±0.011, insulin secretion 〈8.2±1.5 mIU/L）, and the pancreatic islet cells became dispersed, broken or atrophied correspondingly. The differentiated neonatal cells were identified as pancreatic islet cells by dithizone staining method, and pancreatic β-cells were further identified by both morphological features and electrophysiological characteristics, i.e. the existence of recording currents from KATP, Kv, and KCA. CONCLUSION： Islet cells differentiated from neonatal pancreatic duct cells with the new natural protocol are more advantageous in performing patch clamp study over the isolated adult pancreatic islet cells.
文摘The patch clamp recording technique in vivois a blind patch clamp recording methods to record the current of the spinal or cereral neurons of anaes：hesia （ or awake） animals. This technique can be used to study the synaptic function and plasticity in central nervous system in vivoin order to understand the physiological properties of the ion channels from an integrated point of view. The advantage of this technique have already presented itself in the study of the synaptic transmission and nervous network. Nowadays, in vivo patch whole-cell recording technique in combination with other techniques is becoming a common method in the research fields.
基金The authors acknowledge the support of the National Natural Science Foundation of ChinaProvincial Natural Science Foundation of Shanxi.
文摘We used whole-vacuolar patch-clamp recording mode to study the action mechanism of La3+ to Slow Vacuolar (SV) channels for the first time. We recorded SV channel currents of Xinlimei (Raphanus satirus L.) vacuolars. The minimum activation potentials of voltage-dependent SV channels tied in 25+/-5 mV. The increase in cytoplasmic Ca2+ led to enhancement of SV-type currents. It was found that the threshold potential of activation shifted towards more depolarized values whenever cytoplasmic Ca2+ was increased. When 10(-10) mol/L free La3+ was added to the bath, SV-type current was suppressed by 60 similar to 75%. These data showed La3+ reduced ion permeabilities of Xinlimei root vacuolar membrane.
文摘The single ion channel signal is an ionic current that can be recorded by the patch clamp technique. Hidden Markov model (HMM) algorithm has been used to convert the low signal noise ratio (SNR) noisy recording into an idealized quantal one in the case of white background noise. The traditional HMM algorithm is extended and adapted to the colored background noise. A new algorithm called EHMM (Extended HMM) algorithm is proposed, and mainly validated by simulation. Results show that it’s effective.
文摘One kind of novel BLMs was fabricated by patch-clamp pipette technology characterized in considerably sensitive to changes of electrochemical parameters.Detectiye currents and voltage presented linear relationship when BLMs was formed and it could be confirmed by Gramicidin method.Ion current was increased by dihexyl (C_ (12)) modified ssDNA fixed on the BLMs and also indicated linear relationship to ssDNA's concentration due to the interaction of (C_ 12)-ssDNA and BLMs.Further more,the regression equations were different from BLMs fixed with ssDNA probe and a blank control BLM in the same experimental conditions.The ssDNA probe was successfully fixed on patch-clamp pipette supported-BLMs.Based on our studies,a biosensor with reactive element of patch-clamp pipette-supported BLMs has been established.
