title: A note on the evolution of the transducer mechanism of the vertebrate retinal rod.
abstract: The Ca2+-gating mechanism that is the key component of membrane excitability in paramecium has recently been localized on the cilia of this animal. Such a finding shows how the change in Ca2+ permeability (which is the probable consequence of the photoisomerization of rhodopsin) of the discs of the outer segments of the retinal rods could have evolved.
mesh_terms: D000818:Animals; D005075:Biological Evolution; D002118:Calcium / Q000502:physiology; D002923:Cilia / Q000502:physiology; D004594:Electrophysiology; D008564:Membrane Potentials; D010247:Paramecium / Q000502:physiology; D010786:Photoreceptor Cells / Q000502:physiology*; D014714:Vertebrates / Q000502:physiology
chemical_list: D002118:Calcium