Synaptic Ca2+in Darkness Is Lower in Rods than Cones, Causing Slower Tonic Release of Vesicles

• DOI: 10.1523/jneurosci.5386-06.2007
• Publication Date: 2007-05-09T17:14:28Z
• Authors: Zejuan Sheng; Sue-Yeon Choi; Ajay Dharia; Jian Li; Peter Sterling; Richard H. Kramer
• Keywords: Darkness; Rod; Tonic (physiology); Ribbon synapse

Rod and cone photoreceptors use specialized biochemistry to generate light responses that differ in their sensitivity kinetics. However, it is unclear whether there are also synaptic differences affect the transmission of visual information. Here, we report dark, rods tonically release vesicles at a much slower rate than cones, as measured by fluorescent vesicle indicator FM1-43. To determine results from lower Ca 2+ or dark concentration , imaged indicators cycling intraterminal . We indistinguishable consistent with possessing similar machinery. determined two-photon imaging. The level ensures encode intensity better matched information content dim light.