Hi there,
Recently I have been facing an issue where I would get a nice gigaseal with resistance hovering around 1.5-16 gigaohm, but when I am recording channel activity, for 2-3 minutes the baseline would stay flat and stable with Channel openings, but after that the baseline would become unstable and start drooping. I have attached a image of what the droopy recording looks like. No matter how many cell I try it's the same thing.
After it starts drooping I would check the seal again and I can see that the gigaseal is still there intact.
Can someone kindly tell me why this happening?
Our solutions are sodium free and don't have any drugs in them. This was recorded at -50mv in cell attached voltage clamp mode.
Thank you in advance.
If you have a gigaseal, you cannot get an offset from 0 unless there is some large change in your holding potential (Ohm's Law, I=V/R). So either your seal is not stable or your amplifier is not working properly.
Perhaps try to simultaneously record your holding voltage and the currents to check whether your 'drooping' coincides with a sudden change in holding potential. If not, then there must be a change in the resistance.
Can you give us the scale in your picture?
Hi Evgeny, Nope. I don't see anything like that when I am using model cell in Patch mode.
I think my seal is dipping below 1Gohm ocassionally and then resealing itself, which is causing the droopiness.
Hi Martijn, thank you for your reply. I was recording in V-hold/I-hold mode and the holding potential wasn't changed. Probably something with the seal.
Hello Sayeman,
if your seal is stable and maintains GOhmic resistance, then this drops might be channel openings themselves (probably potassium channels). You could check this by clamping the patch at 0 mV (which, if your K concentration is high should stabilize the seal) and at a positive potential like +80 mV which should make these drops go upwards.
Anyway, a big issue that I see in the picture you attach is that you have a masive hum (60 Hz) that you should eliminate for optimal recordings. Do you have any other sample?
Good luck!
Diego
- Badges
- Science topic
- Similar topics
- Biological Science
- Bioecology
- Systems Ecology
- Landscape Ecology
- Connectivity