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Long‐term rod dark adaptation in man. Threshold measurements, rhodopsin regeneration and allosteric sensitivity regulation. An evaluation
Author(s) -
STABELL ULF,
STABELL BJØRN
Publication year - 1996
Publication title -
scandinavian journal of psychology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.743
H-Index - 72
eISSN - 1467-9450
pISSN - 0036-5564
DOI - 10.1111/j.1467-9450.1996.tb00658.x
Subject(s) - rhodopsin , adaptation (eye) , exponent , multiplicative function , term (time) , function (biology) , sensitivity (control systems) , statistical physics , power function , chemistry , value (mathematics) , constant (computer programming) , compensation (psychology) , physics , statistics , mathematics , psychology , mathematical analysis , optics , computer science , biology , quantum mechanics , evolutionary biology , social psychology , philosophy , electronic engineering , linguistics , engineering , retinal , biochemistry , programming language
Recent evidence strongly suggests that the relationship between threshold elevation ( T ) and fraction of bleached rhodopsin ( B ), obtained during a major, middle period of long‐term rod dark adaptation in man, is well described by a power function, i. e., T = k · B n , where k is a multiplicative constant and n is the exponent. Due primarily to the low reliability of measurements of rhodopsin regeneration, however, the exponent n of the power function cannot, at present, be given an exact value. Available information indicates that the value of the exponent ranges between 2.4 and 4. Implications of this uncertainty are discussed within the framework of the allosteric, tetrameric model of rod dark adaptation. It is concluded that this model in its simplest form may only offer a first approximation of the real system implicated in the process.