Barium reverses the transretinal potassium gradient of the amphibian retina

Paul A. Coleman, Peter L. Carras, Robert F. Miller

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8 Scopus citations


Barium chloride (Ba2+) was added to the bathing medium of the perfused retina-eyecup preparation of the tiger salamander. The electroretinogram (ERG) and intraretinal extracellular potassium activity ([K+]o) were analyzed using a double-barrel electrode, one of which was ion-selective for K+. The action of Ba2+ on the ERG was to attenuate the c-wave/slow PIII complex. In addition, Ba2+ dramatically decreased the [K+]o in the outer retina, enough to reverse the transretinal potassium gradient. These findings, together with the known properties of Müller cell K+ channels, form the basis of an explanation of why Ba2+ blocks slow PIII and not the b-wave of the ERG.

Original languageEnglish (US)
Pages (from-to)61-65
Number of pages5
JournalNeuroscience Letters
Issue number1
StatePublished - Sep 11 1987

Bibliographical note

Funding Information:
This work was supportedb y NEI Grant EY008844 and NSF57900t o R.F.M. and NEI trainingG rantEY07057 to P.A.C. and P.L.C.


  • Barium
  • Electroretinogram
  • Potassium-selective electrode
  • Retina
  • Tiger salamander


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