Light and photobiomodulation
Mitochondrial Stimulation
"Mitochondrial stimulation" is an everyday phrase for the proposed effect of red and near infrared light on the mitochondrion: light absorbed by cytochrome c oxidase, nitric oxide displaced, and ATP output raised.
Also called mitochondrial activation, stimulating the mitochondria, cellular energy boost
What is being proposed. Three linked steps, each of which has a proper name:
- Absorption. Red and near infrared photons are absorbed by cytochrome c oxidase, complex IV of the mitochondrial respiratory chain.
- Release. Nitric oxide bound at the enzyme’s oxygen site is displaced, removing an inhibition on electron transport.
- Output. Electron flow resumes more freely, the proton gradient strengthens, and ATP production rises, alongside a brief change in reactive oxygen species that acts as a signal rather than as damage.
What has been shown in cells. A good deal. Raised CCO activity, raised ATP and downstream changes in gene expression after red or near infrared exposure are reported consistently in cultured cells and in animal tissue. Karu’s action-spectrum work (Lasers in Surgery and Medicine, 2005) is the classic demonstration that the response is wavelength-specific in the way a CCO-mediated effect should be.
A useful way to say it. Red and near infrared light are proposed to act on mitochondrial cytochrome c oxidase. That is the mechanism; the outcomes people report belong to the trials that measured them.
Why it matters here
It is the phrase most often used to sum up red light therapy in one sentence. Underneath it sit three specific steps — light absorbed by cytochrome c oxidase, nitric oxide displaced, ATP output raised — which is a more useful thing to know.