low resistance grounding bridges in patch clamp

x011 at Lehigh.EDU x011 at Lehigh.EDU
Fri Apr 28 08:39:48 EST 1995


In article <3nltvg$83n at saba.info.ucla.edu>, chrisdn at physci.lifesci.ucla.edu (chr
istopher del negro) writes:
>has anyone had trouble eliminating noise (line frequency) from patch
>clamp rigs attributable to faulty grounding with an agar bridge electrode?
>
>i have had line frequency problems for about 2 months and have tried many
>forms of grounding and only one was successful in eliminating line freq.
>noise: a simple Ag/AgCl pellet (low res.) in the chamber. it seemed all
>agar bridges were too high resistance and allowed noise to enter the set-
>up. i have recently constructed large diameter bridges which are a bit
>unwieldy in a small chamber such as mine but which apparently have low
>enough resistance to sufficiently ground the preparation and worked well
>for two experiments so far. has anyone else had such a problem?
>
High resistance in the agar bridges.  Hmmm.  In electronics you can dope
a low conductor of electricity with a high conductor.  It is pure
spectulation but Allen J. Bard at UT at Austin reported in Nature
2 March 1995 a new multielectron catalysts that may dope your agar to
the level of conductivity you need so your signal to noise ratio is
higher.  In principle any conductor would work.  Naturally the conductor
you choose can not be the cause of your observations and the doping
agent can not kill your nerve cells.  The best mixing ratios in a
rotating drum is to have the drum 1/4 full according to research
reported in Science.  Ron Blue x011 at lehigh.edu



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