As you will recall, hydrogen sulfide's postulated link to ME/CFS comes from its ability to put mice into a hibernation-like state, where the mice's energy metabolism is reduced to small fraction of normal. I just came across this news item about the fact that adenosine has been found to be the hibernation switch in squirrels. See here for info. My first thought on reading that adenosine causes hibernation in squirrels is whether this discovery may have bearing for chronic fatigue syndrome. In other words: the hibernation-inducing effects of adenosine may provide another possible explanation for the low energy symptoms of ME/CFS. Adenosine is a neurotransmitter that induces sleep. It also plays a role in the heart. And adenosine is of course found bound up the molecule ATP (adenosine triphosphate). Brain cells release ATP which is broken down to adenosine (ref: here), and since the ATP metabolism in chronic fatigue syndrome appears to be dysfunctional (ref: here), it makes you wonder whether excess adenosine may be inadvertently produced in ME/CFS, resulting in the the hibernation-like low energy symptoms of this disease.