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PHOTOSENSORY TRANSDUCTION IN CILIATES. I. AN ANALYSIS OF LIGHT‐INDUCED ELECTRICAL AND MOTILE RESPONSES IN Stentor coeruleus
Author(s) -
Fabczak Stanislaw,
Fabczak Hanna,
Tao Nengbing,
Song PillSoon
Publication year - 1993
Publication title -
photochemistry and photobiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.818
H-Index - 131
eISSN - 1751-1097
pISSN - 0031-8655
DOI - 10.1111/j.1751-1097.1993.tb02940.x
Subject(s) - depolarization , membrane potential , biology , afterdepolarization , biophysics , electrophysiology , neuroscience , repolarization
— Light‐induced membrane potantial changes and motile responses have been studied in Stentor cells with intracellular microelectrodes and video microscopy, respectively. Intracellulae microelectrode showed that step‐up increase in light induced an electrical membrane response which consisted of an initial membrane depolarization (photoreceptor potential) followed by an action potential and maintaining phase of depolarization (afterdepolarization). The amplitude of the receptor potetial is dependent on the intensity of light stimulus and the action potetials appears with a lag period (latency) after the onset of light stimuklus. The extent of the membrane established between the latency for te action poitential and the onset of ciliary reversal (stop responses). A time correlation was also observed between the duration of the membrane afterdepolarization and the duration of backward swimming. the action spectrum for the photoreceptor potential amplitude of Stentor resembled the action spectra for the latency of ciliary reversal and the photoresponsiveness, iondicating that the photomovement response and membrane potential changes are coupled through the same photosensor system. A hypothesis on the photosensory transduction chain in Stentor is discussed according to ehich the photoreceptors and the ciliary apparatus is mediated by the membrane potential canges.