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Setup

  

Electrode Holders

Voltage Electrode - The voltage recording electrode holder uses a silver wire for the 

electrical coupling between the pipette and holder connector. Any silver wire contacting 

the KCl solution in the pipette must be chlorided to reduce junction potentials (see 

Chloriding Procedure in Appendix). The pipette should contain just enough KCl so that 

approximately 1/2 inch of the chlorided wire is submerged. The pipette/holder assembly 

is attached directly to the voltage headstage prior to mounting in a micropositioner. 

 

 

 

NOTE: Do not fill the voltage holder with KCl solution.

Current Electrode - The electrode holder supplied for the current electrode also uses a 

silver wire for coupling. In an manner analogous to the voltage electrode, the current 

electrode wire must also be chlorided prior to assembly and use. The pipette/holder 

assembly is mounted in a micropositioner with the mounting rod supplied.

 
 

NOTE: Do not fill the current holder with KCl solution.

Bath Probe

The bath clamp is designed to maintain a virtual ground in the oocyte perfusate. The 

bath probe should be positioned so that the silver electrode wires can be inserted 

into the recording chamber or into the agar bridge wells. Sticky wax or tape is usually 

sufficient to secure the unit when positioned on a flat surface or, alternatively, the unit 

can be held in place on a separate stand. The bath probe electrodes should also be 

chlorided before use, as described above.

Electrode Placement and Grounding

Three drawings (shown on pages 19 and 20) have been included to illustrate the various 

ways a bath circuit can be configured. Most applications involve only a single oocyte 

and Figures A and B illustrate these setups. Figure C shows a setup for recording from 2 

oocytes in a common bath with the use of dual clamps 

 
 

NOTE: Cable routing must be performed with care. Bundle cables together  

 

rather than routing them individually and keep them as far as possible from  

 

sources of 50/60 Hz interference (e.g., line cords, transformers, etc.). 

Содержание OC-725C

Страница 1: ...Publication 5720 001 REV 1 0 Oocyte Clamp Amplifier User s Manual Warner Instruments OC 725C...

Страница 2: ...ty Compensation Overload Alarm DC Offsets Nomenclature Text conventions Control Description Front panel Voltage electrode Bath electrodes Clamp section Commands Current electrode Rear panel Additional...

Страница 3: ...placement Single oocyte setup with indirect ground Single oocyte setup with direct ground Dual ooctye set up Cable connections Resting position of the controls Using the gain select Other gain range...

Страница 4: ...BJECT Comments and Recommendations Membrane damage Repeated recordings Electrophysiology Appendix Specifications Equipment is intended to be operated in a controlled laboratory environment Gain telegr...

Страница 5: ...ve limitation may not apply to you If a defect arises within the one year warranty period promptly contact Warner Instruments Inc 1125 Dixwell Ave Hamden Connecticut 06514 5014 using our toll free num...

Страница 6: ...grounded Make Proper Connections Make sure all connections are made properly and securely Any signal wire connections to the unit must be no longer than 3 meters Observe All Terminal Ratings Review th...

Страница 7: ...aturation The unique design of the bath clamp eliminates the need for series resistance compensation It provides an accurate measurement of bath current by creating a virtual ground in the bath while...

Страница 8: ...s with a minimum of leakage Electrode Test for voltage and current electrodes Capacity Compensation for the Vm voltage input Overload Alarm serves as a reminder when the feedback amplifier reaches its...

Страница 9: ...conventions which are specified below Since our goal is to provide clarity rather than complexity we welcome any feedback you may wish to provide Warner Instrument product numbers are presented using...

Страница 10: ...hbuttons and the Vm output bnc Controls for negative capacity compensation are also located in this block The voltage meter reports the membrane voltage Vm with a full scale range of 199 9 mV The volt...

Страница 11: ...he voltage Ve of the current electrode when the clamp mode selector switch is off see clamp section A lit LED indicates voltage readings in mV When in clamp mode clamp mode selector switch set to slow...

Страница 12: ...ot required The slow clamp speed is approximately 0 5 ms when measured with the model membrane 1 M shunted with 0 47 F In this mode measured currents are displayed on the BATH ELECTRODES METER in unit...

Страница 13: ...N connector for the current electrode Ve offset With a range of 200 mV center zero this control is used to adjust the offset voltage of the current electrode Use this control to establish a zero refer...

Страница 14: ...located on the rear panel CHASSIS is common with the instrument enclosure and connected to earth through the power line cord A shorting link allows for interconnection of the two grounds In most exper...

Страница 15: ...with two screw mounting slots is attached to the probe base The BATH PROBE connects to the control unit with a 6 pin connector Current Electrode Cable A two meter shielded cable is supplied with a 2 m...

Страница 16: ...ent chassis must be directly connected to earth ground High Voltage Outputs When handling the current electrode cable be sure to set the GAIN CONTROL fully clockwise and the CLAMP MODE switch to off C...

Страница 17: ...y the 10 k resistors Initial Instrument Settings Connect the model cell to the OC 725C as shown on its cover Be sure to connect the ground wire to the ground mini jack on the side of the bath probe Co...

Страница 18: ...is read from the BATH ELECTRODE METER when the CLAMP MODE switch is set to off Ve x10 output BNC This BNC is located on the rear panel of the instrument and reports the setting of the Ve OFFSET contro...

Страница 19: ...ge at the current electrode In this case Ve will be a measure of the voltage across Rm and the meter will indicate 10 mV 1 M DC Clamp Test This test is performed using controls in the CLAMP ELECTRODE...

Страница 20: ...me of the oscilloscope trace become faster since the speed of the clamp is limited by the resistance of the current electrode and the capacitance of the oocyte If ringing oscillation is observed decre...

Страница 21: ...ylgard They will need to be broken off however to a relatively large diameter to insure a fast response time by the clamp For the voltage electrode the pipette tip should be broken back to an O D of 3...

Страница 22: ...the mounting rod supplied NOTE Do not fill the current holder with KCl solution Bath Probe The bath clamp is designed to maintain a virtual ground in the oocyte perfusate The bath probe should be posi...

Страница 23: ...urrent electrode It is recommended that the user not directly expose the electrode wires to the perfusate if the recording session is to last for more than a few minutes Instead agar bridges should be...

Страница 24: ...with the optional DIFFERENTIAL VOLTAGE HEADSTAGE Single Oocyte Setup with Direct Ground Applications where use of the bath clamp is not suitable such as those with a very long solution path to ground...

Страница 25: ...lloscope computer or a chart recorder the following connections should be made Vm Membrane potential may be recorded from the Vm x10 connector VOLTAGE ELECTRODE section Ve The voltage of the current e...

Страница 26: ...election changes the sensitivity of the current meter Typically measured currents will fall in the x1 range The lower and higher ranges are intended to cover those applications where currents are beyo...

Страница 27: ...odified model cell All readings were recorded at 1 kHz 8 pole Bessel and are RMS A lower value feedback resistor increases the speed of the bath clamp and can handle larger currents without saturating...

Страница 28: ...f there is a bubble in the pipette which will cause an open circuit 5 Using the Vm OFFSET control adjust the VOLTAGE ELECTRODE potential to read 0 mV If the junction potential of the voltage electrode...

Страница 29: ...ance the voltage electrode until it pops through the membrane 12 The potential across the membrane will now be displayed on the VOLTAGE ELECTRODE METER Current Electrode Placement Advance the current...

Страница 30: ...GAIN mode CLAMP section may be required to clamp high conductance low resistance cells This condition will be evidenced by the inability of the instrument to maintain a DC holding potential to within...

Страница 31: ...sition fully counter clockwise to click off as described above and the CLAMP MODE selector switch be placed in the off position before removing the current electrode from the cell Failure to perform t...

Страница 32: ...y setting a dip switch on the main circuit board 1 First disconnect the power cord from the wall 2 Remove the two screws at the rear of the top cover and it off 3 Locate dip switch S10 on the circuit...

Страница 33: ...he same resistance as they had in the previous recording A significantly higher resistance could indicate that the pipette is partially plugged with cellular debris Make the following control settings...

Страница 34: ...and UV filtered if you plan to use it during recording Minimally the recording chamber can be a stable surface on which the oocyte will not roll around A disposable petri dish with a piece of nylon me...

Страница 35: ...F Vm Meter Range full scale 199 9 mV Bath electrode channel Im Ve OFFSET 200 mV Noise Im Clamp clamp on 5 5 nA RMS at 1 kHz x1 range Open loop clamp off 28 pA RMS at 1 kHz x1 range I MONITOR 0 01 100...

Страница 36: ...0 1 V command attenuated by 10 Maximum external input 10 V Power requirements 100 120 v 0 5A or 220 240 VAC 50 60 Hz Fuse 0 5A 120v slow blow 0 15A 200v slow blow Appendix Dimensions Enclosure 9 x 42...

Страница 37: ...1 4 V 2 1 6 V 5 1 8 V 10 2 0 V 20 2 2 V 50 2 4 V 100 2 6 V Gain Select Headstage Resistor Im Output Range V A Im max output A Maximum Meter Reading x0 1 10 k 0 01 1 0 10 1000 199 9 A x1 0 100 k 0 1 10...

Страница 38: ...Xenopus oocytes Transcription and Translation eds B D Hames and S J Higgins IRL Press Oxford Ch 10 Hille B 1984 Ionic Channels of Excitable Membranes Sinauer Sunderland MA Ch 2 Zhou J Potts J F Trimme...

Страница 39: ...38 Publication 5720 001 REV1 0 Notes...

Страница 40: ...39 www warneronline com Notes...

Страница 41: ...40 Publication 5720 001 REV1 0 Notes...

Страница 42: ......

Страница 43: ...746 Phone 508 893 8999 Toll Free 800 272 2775 Fax 508 429 5732 E mail support hbiosci com Web www harvardapparatus com Germany Hugo Sachs Elektronik Gruenstrasse 1 March Hugstetten D 79232 Germany Pho...

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