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Photochemically produced intracellular concentration jumps of cAMP mimic the effects of catecholamines on excitation-contraction coupling in frog atrial fibers

Richard, Sylvain and Nerbonne, Jeanne M. and Nargeot, Joel and Lester, Henry A. and Garnier, Didier (1985) Photochemically produced intracellular concentration jumps of cAMP mimic the effects of catecholamines on excitation-contraction coupling in frog atrial fibers. Pflügers Archiv European Journal of Physiology, 403 (3). pp. 312-317. ISSN 0031-6768. https://resolver.caltech.edu/CaltechAUTHORS:20201020-073939931

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Abstract

Previously, we reported that concentration jumps of cAMP produced by light flashes in the presence of a photosensitive analogue of cAMP increase the amplitude of the slow inward current (I_(si)) in isolated bullfrog atrial trabeculae (Nargeot et al. 1983). Here, using newly designed photolabile cyclic nucleotides (Nerbonne et al. 1984a), we have examined the effects of intracellular concentration jumps of cAMP and cGMP on excitation-contraction coupling in frog heart. Concentration jumps of cAMP increase the amplitude and the duration of action potentials, increase I_(si) and twitch tension. Following single flashes, maximum responses are observed in 10–30 s and recovery times are 30–120 s. The time courses of the cAMP-induced increases in I_(si) and phasic tension amplitudes are parallel, implying a direct correlation between Ca²⁺ influx through the slow channels and the development of phasic tension. Although the amplitudes are increased severalfold, cAMP jumps do not measurably alter the kinetics or voltage dependences of the current or tension. cAMP concentration jumps increase the delayed K⁺ current (I_K) and decrease tonic tension; relaxation of contraction is not, however, influenced by cAMP jumps. Concentration jumps of cGMP, on the other hand, have no measurable effects on the action potential, I_(si), I_K or tension in this preparation.


Item Type:Article
Related URLs:
URLURL TypeDescription
https://doi.org/10.1007/bf00583606DOIArticle
ORCID:
AuthorORCID
Lester, Henry A.0000-0002-5470-5255
Additional Information:© 1985 Springer. Received 04 July 1984; Accepted 03 December 1984.
Subject Keywords:cAMP; Slow inward current; Phasic tension; Tonic tension; K outward currents
Issue or Number:3
Record Number:CaltechAUTHORS:20201020-073939931
Persistent URL:https://resolver.caltech.edu/CaltechAUTHORS:20201020-073939931
Official Citation:Richard, S., Nerbonne, J.M., Nargeot, J. et al. Photochemically produced intracellular concentration jumps of cAMP mimic the effects of catecholamines on excitation-contraction coupling in frog atrial fibers. Pflugers Arch. 403, 312–317 (1985). https://doi.org/10.1007/BF00583606
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:106158
Collection:CaltechAUTHORS
Deposited By: Tony Diaz
Deposited On:20 Oct 2020 20:49
Last Modified:20 Oct 2020 20:49

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