Increase in the ADP/ATP exchange in rat liver mitochondria irradiated in vitro by helium-neon laser

Biochem Biophys Res Commun. 1988 Oct 31;156(2):978-86. doi: 10.1016/s0006-291x(88)80940-9.


To gain some insight into the mechanism of cell photostimulation by laser light, measurements were made of the rate of ADP/ATP exchange in mitochondria irradiated with the low power continuous wave Helium Neon laser (energy dose 5 Joules/cm2). To do this a method has been developed to continuously monitor ATP efflux from phosphorylating mitochondria caused by externally added ADP, by photometrically following the NADP+ reduction which occurs in the presence of glucose, hexokinase, glucose-6-phosphate dehydrogenase and effluxed ATP. The NADP+ reduction rate shows hyperbolic dependence on ADP concentration (Km and Vmax values 8.5 +/- 0.87 microM and 20.7 +/- 0.49 nmoles NADP+ reduced/min x mg mitochondrial protein, respectively), and proves to measure the activity of the ADP/ATP translocator as shown by inhibition experiments using atracyloside, powerful inhibitor of this carrier. Irradiation was found to enhance the rate of ADP/ATP antiport, with externally added ADP ranging between 5 and 100 microM. As a result of experiments carried out with mitochondria loaded with either ATP or ADP, the increase in the activity of the ADP/ATP translocator is here proposed to depend on the increase in the electrochemical proton gradient which occurs owing to irradiation of mitochondria.

MeSH terms

  • Adenosine Diphosphate / metabolism*
  • Adenosine Diphosphate / pharmacology
  • Adenosine Triphosphate / metabolism*
  • Animals
  • Atractyloside / pharmacology
  • Electrochemistry
  • Glucose / metabolism
  • Glucosephosphate Dehydrogenase / metabolism
  • Hexokinase / metabolism
  • Kinetics
  • Lasers*
  • Mitochondria, Liver / drug effects
  • Mitochondria, Liver / metabolism
  • Mitochondria, Liver / radiation effects*
  • NADP / metabolism
  • Oligomycins / pharmacology
  • Oxidation-Reduction
  • Phosphorylation
  • Rats
  • Spectrophotometry


  • Oligomycins
  • Atractyloside
  • NADP
  • Adenosine Diphosphate
  • Adenosine Triphosphate
  • Glucosephosphate Dehydrogenase
  • Hexokinase
  • Glucose