I have a steady temp. control system in my ephys rigs which can easily heat up the ACSF just before it reaches the recording chamber.
Is it nessesary to keep the solution also warm in the main reservoir (1l bottle outside of the faraday cage) where I bubble the solution with 95%O2/5%CO2?
I dont have problems with degassing, and the solution cools down anyway before reaching the chamber.
Or would bubbling on room temperature mess up the pH enough that it doesnt stabilize when preheating just before the chamber?
The perfusion rate is pretty low, around 1ml/min.
I have never preheated my Ringer/Ames solutions and I never had problems with perfusion or cell viability. I also measured different solutions (Hepes ringer/Ames) with different conditions, with an oxygen meter. Hepes ringer (45 min) was the most stable, but carbonate-buffered ringer was also stable for 15 min without oxigentation on 32 degrees.
The perfusion rate is OK. But I would recommend to keep the aCSF much warmer than the room temp, around 36-38 degrees centigrade. I had problems with GrDG neurons and I realized that other than the importance of fixed flow rate of aerated aCSF, the temp can effect pH too leading to dead or less suitable cells (turgid cells and membrane burst).
This would prevent any pH instability or fluctuation of osmolarity while bubbling it (aerating with carbogen) during patch.
I've done brain and retinal slices and I did not pre-heat my main vessel.
I have never pre-heated the ACSF. However, I have always used a bath heater to keep the solution in the chamber at 32-34 degC.
Thank you, my feeling was also that the direct chamber heater is sufficient - makes things a bit more tidy also
If you directly heat your chamber, that could result in some noise in your recordings. That's why I have always used an inline heater just before the inflow grounded with a stainless steel tube.
Hello,
a lot of experimenters pre-heat their recording solution twice: First during carbogenating (usually in a rather inaccurate water bath) and then with a more precise system directly before the solution enters the chamber. This is not meant to prevent degassing, but rather to prevent precipitation.
Carbogen solubility is temperature dependent and, especially in the range of 20 - 40° C, decreases with rising temperature. If you were to initially dissolve carbogen in your solution at room temperature and later pre-heat your solution, odds are that carbogen will precipitate in your chamber (you might see bubbles).
While this is mostly inconsequential in patch-clamp recordings, I can imagine that MEA recordings might be affected by this.
- Badges
- Science topic