Hi Sophie,

I always use WPI EP1 (1mm diameter). It works fine. After soldering I cover a tiny piece of the pellet with a heat shrink tube and seal it with super glue. I use it both for extracell or patch clamp recordings with digidata 1440A, Clampex 10.4 and Multiclampex700B.

Good luck.

Hi Sophie

Anything unusual in your ACSF? What flow rates do you use? How many agonists do you co-perfuse? I'm wondering if you are getting some precipitate in your bathing solution that concentrates around the ground. Very strange problem.

Cheers

John

Dear Sophie,

I would just make my own ground wire. Just get the thickest possible silver wire and chlorinate it bleach for 20 mins. Wash and rinse well in deionised water. Dry it and do not touch it with your fingers (due to enzymes in your skin) use glows or forceps when you touch the chlorinated bit. Of course that would have to soldiered into your connecting ground wire. This should work you are using normal extra cellular solutions with around 150 mM chloride. I record from brain slices with no problem. Just make sure whenever you chlorinate your ground also chlorinate your silver wire that goes into  your glass pipette and contacts internal solution.

Best wishes,

Refik

Article Semi-loose seal Neurobiotin electroporation for combined str...

Article Neurobiotin Electroporation for Combined Structural and Func...

Technical Report Research Methods and Technical Considerations: Answers to ov...

Dear Sophie, 

Seems like the coating of the bath electrode is the main reason of depletion. Probably, oxigenation makes some components of aCSF less soluble, especially if you use pre-heating of aCSF. Worse if there is a chemical reaction with some of components (or vehicles - e.g. cyclodextrin). But it's unlikely.

Anyway I would try to isolate the bath electrode chemically. For example, you can start with this simple and smart idea:

http://www.heka.com/downloads/hardware/manual/m_epc10.pdf (page 50)

Good luck!

Hi Sophie,

I always use WPI EP1 (1mm diameter). It works fine. After soldering I cover a tiny piece of the pellet with a heat shrink tube and seal it with super glue. I use it both for extracell or patch clamp recordings with digidata 1440A, Clampex 10.4 and Multiclampex700B.

Good luck.

I really wonder to see this problem, may be  precipitation of the of the ground  electrode of some salt only you should put  the  ground electrode for some time in oxygemated buffur and see after 30 mini if any change is visible.

good luck