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Abstract <p>Although cyclic adenosine monophosphate (cAMP) is not themain player in the process of phototransduction, it can modulateit. The effects of cAMP have been widely studied in rods, but itsrole in the photoreceptors responsible for daytime vision, the cones,has not been thoroughly investigated. The aim of this study wasto eхamine the impact of increased intracellular cAMP levels onthe photoresponse kinetics and light sensitivity of red-sensitive cones(RCs) in the retinas of adult zebrafish (<i>Danio rerio</i>).Two electrophysiological methods were employed in this study: exvivo electroretinography with isolating the responses of RCs, andsingle photoreceptor current recordings performed using a suctionpipette. The adenylate cyclase activator forskolin was used to increaseintracellular cAMP levels. The investigation of response characteristics revealedthat forskolin did not affect the sensitivity of RCs compared tocontrols. A detailed analysis of the kinetics of the unsaturatedresponse of RCs showed that forskolin, similarly to its effectson amphibian rods and zebrafish blue- and green-sensitive cones, sloweddown the process of turning off the phototransduction cascade, whilesimultaneously increasing the integration time of the response.The activation stages of the cascade remained unaffected by forskolin.At the same time, a closer examination of the rising phase of thephotoresponse near its peak revealed that the faster stage of thecascade turning off was further accelerated by the action of forskolin. Collectively,these data indicate that an increase in intracellular cAMP levelscan modulate the phototransduction cascade in zebrafish RCs; however, unlikeother studied spectral cone types, it does not alter their lightsensitivity. The most significant modulation likely occurs in thecascade turning off processes of RCs.</p>

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The Involvement of cAMP in the Adaptation of Red-Sensitive Cones in Zebrafish: an Electrophysiological Study at the Level of Single Cells and the Entire Retina

  • 期刊论文

  • 发表日期：

    2025年12月19日

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  • Ya. S. Veselov,
  • G. E. Gromova,
  • A. D. Kalita,
  • D. A. Nikolaeva,
  • L. A. Astakhova

摘要

Abstract

Although cyclic adenosine monophosphate (cAMP) is not themain player in the process of phototransduction, it can modulateit. The effects of cAMP have been widely studied in rods, but itsrole in the photoreceptors responsible for daytime vision, the cones,has not been thoroughly investigated. The aim of this study wasto eхamine the impact of increased intracellular cAMP levels onthe photoresponse kinetics and light sensitivity of red-sensitive cones(RCs) in the retinas of adult zebrafish (Danio rerio).Two electrophysiological methods were employed in this study: exvivo electroretinography with isolating the responses of RCs, andsingle photoreceptor current recordings performed using a suctionpipette. The adenylate cyclase activator forskolin was used to increaseintracellular cAMP levels. The investigation of response characteristics revealedthat forskolin did not affect the sensitivity of RCs compared tocontrols. A detailed analysis of the kinetics of the unsaturatedresponse of RCs showed that forskolin, similarly to its effectson amphibian rods and zebrafish blue- and green-sensitive cones, sloweddown the process of turning off the phototransduction cascade, whilesimultaneously increasing the integration time of the response.The activation stages of the cascade remained unaffected by forskolin.At the same time, a closer examination of the rising phase of thephotoresponse near its peak revealed that the faster stage of thecascade turning off was further accelerated by the action of forskolin. Collectively,these data indicate that an increase in intracellular cAMP levelscan modulate the phototransduction cascade in zebrafish RCs; however, unlikeother studied spectral cone types, it does not alter their lightsensitivity. The most significant modulation likely occurs in thecascade turning off processes of RCs.