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Proceedings of the National Academy of Sciences of the United States of America logoLink to Proceedings of the National Academy of Sciences of the United States of America
. 1969 Dec;64(4):1230–1234. doi: 10.1073/pnas.64.4.1230

PHOTOREGULATION OF BIOLOGICAL ACTIVITY BY PHOTOCHROMIC REAGENTS, III. PHOTOREGULATION OF BIOELECTRICITY BY ACETYLCHOLINE RECEPTOR INHIBITORS*

Walter J Deal 1,2, Bernard F Erlanger 1,2, David Nachmansohn 1,2
PMCID: PMC223273  PMID: 5271749

Abstract

The photochromic compounds N-p-phenylazophenyl-N-phenylcarbamylcholine chloride and p-phenylazophenyltrimethylammonium chloride inhibit the carbamylcholine-produced depolarization of the excitable membrane of the monocellular electroplax preparation of Electrophorus. The trans isomer of each predominates in the light of a photoflood (420 mμ) lamp; they are stronger inhibitors than the cis isomers, which predominate under ultraviolet (320 mμ) irradiation. The potential difference across the excitable membrane may be photoregulated by exposing an electroplax in the presence of a solution of carbamylcholine and either of the two compounds to light of appropriate wavelengths, since light shifts the cis-trans equilibrium. The system may be considered as a model illustrating how one may link a cis-trans isomerization, the first step in the initiation of a visual impulse, with substantial changes (20-30 mv) in the potential difference across an excitable membrane.

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Selected References

These references are in PubMed. This may not be the complete list of references from this article.

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