Properties of multivesicular release from mouse rod photoreceptors support transmission of single-photon responses

eLife

Asia L Sladek¹  Wallace B Thoreson²  Greg D Field³  Cassandra L Hays⁴ 

[1] Cellular and Integrative Physiology, Omaha, United States;Department of Neurobiology, Duke University School of Medicine, Durham, United States;Pharmacology and Experimental Neuroscience, Omaha, United States;Truhlsen Eye Institute and Department of Ophthalmology and Visual Sciences, College of Medicine, University of Nebraska Medical Center, Omaha, United States;

关键词: scotopic vision;    rod photoreceptor cell;    synaptic vesicle release;   

DOI  :  10.7554/eLife.67446

来源: DOAJ

【 摘 要 】

Vision under starlight requires rod photoreceptors to transduce and transmit single-photon responses to the visual system. Small single-photon voltage changes must therefore cause detectable reductions in glutamate release. We found that rods achieve this by employing mechanisms that enhance release regularity and its sensitivity to small voltage changes. At the resting membrane potential in darkness, mouse rods exhibit coordinated and regularly timed multivesicular release events, each consisting of ~17 vesicles and occurring two to three times more regularly than predicted by Poisson statistics. Hyperpolarizing rods to mimic the voltage change produced by a single photon abruptly reduced the probability of multivesicular release nearly to zero with a rebound increase at stimulus offset. Simulations of these release dynamics indicate that this regularly timed, multivesicular release promotes transmission of single-photon responses to post-synaptic rod-bipolar cells. Furthermore, the mechanism is efficient, requiring lower overall release rates than uniquantal release governed by Poisson statistics.

【 授权许可】

Unknown