title: Acidification of the synaptic cleft of cone photoreceptor terminal controls the amount of transmitter release, thereby forming the receptive field surround in the vertebrate retina.
abstract: In the vertebrate retina, feedback from horizontal cells (HCs) to cone photoreceptors plays a key role in the formation of the center-surround receptive field of retinal cells, which induces contrast enhancement of visual images. The mechanism underlying surround inhibition is not fully understood. In this review, we discuss this issue, focusing on our recent hypothesis that acidification of the synaptic cleft of the cone photoreceptor terminal causes this inhibition by modulating the Ca channel of the terminals. We present evidence that the acidification is caused by proton excretion from HCs by a vacuolar type H(+) pump. Recent publications supporting or opposing our hypothesis are discussed.
authors: Laboratory for Neuroinformatics, Riken Brain Science Institute, Wako, Saitama, 351-0198, Japan.
authors: Hajime
authors: H
authors: Hirasawa
authors: Masahiro
authors: M
authors: Yamada
authors: Akimichi
authors: A
authors: Kaneko
mesh_terms: D000200:Action Potentials / Q000502:physiology; D000818:Animals; D015220:Calcium Channels / Q000502:physiology; D006863:Hydrogen-Ion Concentration; D008564:Membrane Potentials / Q000502:physiology; D018377:Neurotransmitter Agents / Q000502:physiology*; D010775:Photic Stimulation / Q000379:methods; D017729:Presynaptic Terminals / Q000502:physiology*; D017494:Proton Pumps / Q000502:physiology; D012160:Retina / Q000502:physiology*; D017949:Retinal Cone Photoreceptor Cells / Q000502:physiology*; D014714:Vertebrates / Q000502:physiology*; D005680:gamma-Aminobutyric Acid / Q000494:pharmacology
chemical_list: D015220:Calcium Channels; D018377:Neurotransmitter Agents; D017494:Proton Pumps; D005680:gamma-Aminobutyric Acid