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PHOTO‐ELECTRIC EFFECTS IN BILAYER MEMBRANES; ELECTROMETERS AND VOLTAGE CLAMPS COMPARED
Author(s) -
HUEBNER JAY S.,
ARRIETA RODOLFO T.,
ARRIETA IRIS C.,
PACHORI PAPPI M.
Publication year - 1984
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.1751-1097.1984.tb03427.x
Subject(s) - cyanine , chromophore , chemistry , voltage , voltage clamp , membrane , photoelectric effect , aqueous solution , photochemistry , bromide , flash photolysis , analytical chemistry (journal) , optoelectronics , materials science , membrane potential , reaction rate constant , optics , inorganic chemistry , organic chemistry , kinetics , electrical engineering , fluorescence , physics , engineering , biochemistry , quantum mechanics
— Laser flash induced voltage transients recorded with high speed electrometers are compared to signals generated by voltage clamps, using chromophores which generate photo‐electric effects in membranes by different mechanisms and with time constants that varied from < 100 ns to > 1 s. The chromophores used were; (i) azo dye, 3,3‐bis‐(α‐(trimethylammonium)methyl) azobenzene‐bromide, (ii) cyanine dye, 3,3‐dimethyl‐2,2‐oxacarbocyanine‐chloride, (iii) xanthene dye, 2,4, 5, 7‐tetraiodofluorescein or erythrosin, and (iv) chlorophyll a . A scheme for classifying photo‐electric effects is presented. Voltage clamp signals are functions of both apparatus and photo‐current time constants. They vary with aqueous solution salt concentration, and usually mask kinetic information that may be obtained with electrometers.