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Bad luck with patching... any tips?

BilZ0r BilZ0r at TAKETHISOUThotmail.com
Sat Dec 11 05:36:11 EST 2004


usenet01 at out-of-phase.de (Christian Wilms) wrote in 
news:1go0pid.1u0hrgn1le0vv2N%usenet01 at out-of-phase.de:

> tomte <tehgabriel at web.de> wrote:
> 
>> I use pipettes with the same parameters (3MOhm, K-Gluc.) and they work
>> perfectly. But sure it may be one point you can check. Usually
>> increasing the pipette resistance (up to 5-6 MOhm, don't go higher)
>> will result in getting better seals but your access resistance gets
>> worse.
> Of course the pipette resitance alone is not necessarily a suffient
> description of the pipettes. Remembering things which have been a
> problem in my work I would recommend having a good look at the tips:
> -are the surfaces where the glass tore smooth or do they appear rough
> -what is the geometry of the pipettes? Just conical or are they formed
> slightly more parabolic?
> 
> There is a good chapter on tip geometry in "Single Channel Recording"
> 
> Though, reading the rest of the OPs Post, I have the impression, that
> the tips are not the issue here. The despcription he gives sounds more
> like he's patching "gunk" instead of cells. I have very little
> experience with blind patching (which is what he appears to be trying),
> but believe to remember, that there should be a more drastic change in
> the current response to the test-pulse when the pipette opening is 
close
> to a cell.
> 
> h2h, Chris
> 

In the end, I didn't change anything... after putting up with what we 
thought was a weeks dead slices (actually, the stimulator was just 
broken), I finally got back to patching, and hit 3 impalements out of 4 
approaches!

Thanks everyone



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