These tools will no longer be maintained as of December 31, 2024. Archived website can be found here. PubMed4Hh GitHub repository can be found here. Contact NLM Customer Service if you have questions.


Pubmed for Handhelds

PUBMED FOR HANDHELDS

Search MEDLINE/PubMed

  • Title: Current source density analysis of retinal field potentials. II. Pharmacological analysis of the b-wave and M-wave.
    Author: Xu X, Karwoski CJ.
    Journal: J Neurophysiol; 1994 Jul; 72(1):96-105. PubMed ID: 7965036.
    Abstract:
    1. The actions of two pharmacological agents, barium ions (Ba2+) and picrotoxin (PTX), were examined on components of the electroretinogram (ERG) in frog retina. Depth profiles of light-evoked field potentials were recorded, and current source densities (CSDs) were computed from these. 2. Ba2+ abolished the M-wave, slow PIII, and the c-wave, but only decreased b-wave amplitude down to approximately 65% of control amplitude. 3. Ba2+ abolished a slow current sink in the inner plexiform layer (IPL) and the source at the inner limiting membrane (ILM). This IPL sink/ILM source appears to generate the M-wave. 4. Ba2+ decreased the current sink at the outer plexiform layer (OPL) to approximately 70% of control amplitude, and it increased an IPL source. This Ba(2+)-resistant OPL sink/IPL source appears to generate a significant portion of the b-wave. The Ba(2+)-sensitive portion of the b-wave might be generated by Müller cells. 5. PTX enhanced retinal field potentials, particularly the M-wave in the proximal retina. This enhanced M-wave was shown to originate from an enhanced IPL sink/ILM source. 6. Our results suggest that the M-wave originates from Müller cells, through the spatial buffering of the light-evoked increase in [K+]o of the proximal retina. A portion of the b-wave may also originate from Müller cells, but a stronger direct contribution from depolarizing bipolar cells is suggested.
    [Abstract] [Full Text] [Related] [New Search]