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Published March 24, 1977 | public
Journal Article

Response of acetylcholine receptors to rapid photochemically produced increases in agonist concentration

Abstract

SYNAPTIC transmission to muscle fibres and electroplaques takes place on a millisecond timescale. To study the molecular events leading to activation of the cholinergic receptor channel, we have developed a method to produce similarly rapid, spatially uniform steps of agonist concentration near intact postsynaptic membranes. Electrophorus electroplaques in a voltage-clamp apparatus were exposed to a solution containing a photochromic compound. Initially the compound was in a predominantly cis form, which had little effect on the membrane. During a brief light flash, some of the compound was isomerised to the trans isomer, which is a cholinergic agonist. As a result the membrane conductance increased along a timecourse which reflects the rate processes underlying activation of the cholinergic receptor channel.

Additional Information

© Nature Publishing Group 1977. Received 01 November 1976. Accepted 25 January 1977. We thank D. Williams for assistance with the animals, W. L. Crowder for help with electronics, D. D. Koblin for participating in some of the experiments, M. A. Raftery for the use of a spectrophotometer, E. Neumann for helpful discussion, and the Chadwick-Helmuth Corporation (Monrovia, California) for the loan of a flash tube and power supply. This work was supported by the NIH, by the Muscular Dystrophy Association, and by an Alfred P. Sloan Fellowship to H.A.L.

Additional details

Created:
August 19, 2023
Modified:
October 20, 2023