The energetic cost of photoreception in retinal rods of mammals
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Updated: Sep 11, 2026

Preparation of Living Isolated Vertebrate Photoreceptor Cells for Fluorescence Imaging
Published on: June 22, 2011
G C Demontis1, B Longoni, C Gargini
1Istituto Policattedra di Discipline Biologiche, Università di Pisa, Italy.
Abstract:
The effects of temperature on rod sensitivity and adaptation are analysed in the general context of the energy requirements of photoreception. The dependence of adaptation on the [Na]i turn-over appears to be critical in mammalian rods where the metabolic load is particularly heavy because of both temperature conditions and large Na+ influx. Estimates of the energy dissipated by rods in darkness and during bright illumination show that the metabolic load is reasonably well distributed. From this analysis it also results that most of the energy, which a rod dissipates in both darkness and light, is needed to keep [Na]i and [Ca]i low.
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