The role of ribbons at sensory synapses.
Synaptic ribbons are organelles that tether vesicles at the presynaptic active zones of sensory neurons in the visual, auditory, and vestibular systems. These neurons generate sustained, graded electrical signals in response to sensory stimuli, and fidelity of transmission therefore requires their synapses to release neurotransmitter continuously at high rates. It has long been thought that the ribbons at the active zones of sensory synapses accomplish this task by enhancing the size and accessibility of the readily releasable pool of synaptic vesicles, which may represent the vesicles attached to the ribbon. Recent evidence suggests that synaptic ribbons immobilize vesicles in the resting cell and coordinate the transient, synchronous release of vesicles in response to stimulation, but it is not yet clear how the ribbon can efficiently mobilize and coordinate multiple vesicles for release. However, detailed anatomical, electrophysiological, and optical studies have begun to reveal the mechanics of release at ribbon synapses, and this multidisciplinary approach promises to reconcile structure, function, and mechanism at these important sensory synapses.
LoGiudice
Lisamarie
L
Department of Neurobiology and Behavior, State University of New York, Stony Brook, New York 11794-5230, USA.
Matthews
Gary
G
D000818:Animals; D006801:Humans; D008561:Membrane Fusion / Q000502:physiology; D009420:Nervous System / Q000648:ultrastructure*; D015388:Organelles / Q000502:physiology / Q000648:ultrastructure*; D011984:Sensory Receptor Cells / Q000502:physiology / Q000648:ultrastructure*; D013569:Synapses / Q000502:physiology / Q000648:ultrastructure*; D055366:Synaptic Potentials / Q000502:physiology; D009435:Synaptic Transmission / Q000502:physiology*; D013572:Synaptic Vesicles / Q000502:physiology / Q000648:ultrastructure