Hi all ! Well, I'm trying to patch cells in hippocampus organotypic slices. My pipette resistance is around 3-4 MOhm. Usually, when I patch, I have to inject a current less than -200 pA to maintain the potential at -65 mV. But now I'm configurating a new rig and I have some bugs with the software (Clampex10, Ampli 700B, Digidata 1550A) : when I am in Membrane Test, the current is closed to -15 000 pA. And when I'm in patch-clamp mode, I have to inject a current close to -1000 pA to maintain the potential at -65 mV.
Everything seems to be ok when I use the model cell.
Does someone already had this problem ? How can I fix it ?
Thanks for your help !
Hi Noemie,
It sounds like you have a problem of gain somewhere... Make sure all the calibrations are correct. Also, have you tried to measure with an oscilloscope what really comes out of the amplifier?
Hi Noemie,
I agree with what Norbert said above. I just want to add that the problem you have is most likely due to wrong gain settings. I would recommned that you go back to your configuration in the program and chick all the gain settings. Also check the gain in the headstage and also the gain setting of your amlifier.
Best wishes,
Refik
Assuming that there is no problem on gain setting, the difference could be due to recordings made in either whole-cell or cell-attached configuration. Sometimes, cells are rather small and difficult to detect the configuration made under whole-cell or cell-attached condition. Under cell-attached mode, the input resistance could become greater.
I all and thanks for your prompt reply.
So, there was an incompatibility between the two softwares Clampex and Multiclamp (I needed to update the devices). I reinstalled both of them, and configured everything and now it works perfectly ! Sometimes the things go wrong and the reason is completely away from what we think at the beginin^^
Hello, I guess, an oscilloscope fitted to the amplifier would have helped immediately to uncover the bug. The scope always shows the real life, it never (or usually at least...) fails. Imre
- Badges
- Science topic