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On the metabolism of the rod outer segments.
Author(s) -
Carretta A,
Cavaggioni A
Publication year - 1976
Publication title -
the journal of physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.802
H-Index - 240
eISSN - 1469-7793
pISSN - 0022-3751
DOI - 10.1113/jphysiol.1976.sp011392
Subject(s) - rod , phosphate , rhodopsin , extracellular , chemistry , darkness , ion , high energy phosphate , ionophore , metabolism , biophysics , firefly protocol , calcium , energy metabolism , biochemistry , biology , botany , organic chemistry , endocrinology , medicine , retinal , alternative medicine , pathology , phosphocreatine , zoology
1. The high energy phosphate esters available for the luminescent reaction of the firefly lantern extract correspond, in the dark adapted rods of the frog, to 7 X 10(‐16) mole of ATP per rod, corresponding to ca. 1‐4 mM. 2. Rods isolated from light adapted eyes contain a smaller amount. 3. The high energy phosphate esters are reduced spontaneously at a rate of 50% in 24 min, in the isolated rods in darkness. 4. Bleaching a few per cent of the rhodopsin molecules of a rod suspension induces a 60% decrease achieved in less than 12 sec. 5. The ionophore A23187 decreases the high energy phosphate esters when the extracellular free Ca concentration is greater than 10(‐7) M, suggesting that ATP is consumed in pumping Ca ions out of the rods, or into the disks contained in the rods, or both.