Medicine and Health Sciences Commons^™

Properties Of Multivesicular Release From Mouse Rod Photoreceptors Support Transmission Of Single-Photon Responses, Cassandra L. Hays, Asia L. Sladek, Greg D. Field, Wallace B. Thoreson

Journal Articles: Ophthalmology

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 …