Oxygen uptake occurs faster than sodium pumping in bee retina after a light flash

Tsacopoulos, M., Orkand, R. K., Coles, J. A., Levy, S. and Poitry, S. (1983) Oxygen uptake occurs faster than sodium pumping in bee retina after a light flash. Nature, 301(5901), pp. 604-606. (doi: 10.1038/301604a0)

Abstract

When neurones are active there is an entry of Na+, which must subsequently be pumped out, and an increase in their oxygen consumption rate (Q o2). The Na+ pump derives its energy from ATP, splitting it into ADP and Pi, and it has reasonably been proposed that the changes in concentrations of ATP, ADP and Pi lead to a stimulation of the O2 consumption by the mitochondria and hence to a restoration of the stock of ATP1–3. Here we present evidence suggesting that Q o2 must be controlled differently in the retinal photoreceptor cells of the honeybee drone. Stimulation of drone photoreceptors with a flash of light causes an entry of Na+ (ref. 4) and a transient increase in Q o2 that indicates respiration of the right order of magnitude to provide ATP to pump the Na+ out5. We report intracellular recordings of changes in intracellular sodium (Nai +) and potassium (Ki +) in response to single light flashes and have compared the time course of extra oxygen consumption (ΔQ o2) with these ion changes and other indices of Na+ pumping. We found that the time course of pumping seems to lag behind the time course of ΔQ o2. It follows that the mitochondrial respiration must be stimulated by some signal which is generated earlier than the rise in ADP produced by the Na+ pump.

• Item Type: Articles
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Coles, Dr Jonathan
• Authors: Tsacopoulos, M., Orkand, R. K., Coles, J. A., Levy, S., and Poitry, S.
• College/School: College of Medical Veterinary and Life Sciences > School of Infection & Immunity
• Journal Name: Nature
• Publisher: Nature Publishing Group
• ISSN: 0028-0836
• ISSN (Online): 1476-4687