There is a discourse on cyclic AMP (cyclic adenosine monophosphate) in a book called Sunlight by Zane Kime MD, MS. Some foods that could contribute to excess cAMP are tea, coffee, and chocolate, because they block cyclic AMP destruction. Prostaglandin E1 and E2, adrenalin, and histamine (got this from a medical textbook) stimulate cells to produce cyclic AMP.

Visible light from the sun penetrates the body (even the brain) and decreases cAMP levels. This produces a relaxation effect. (I have been looking at the book as I have been writing this). Zane Kime was way before his time and unfortunately died before his time in a mountain climbing accident. I tried to contact him once and found this out from the publisher. The book was published 18 years ago and is still in print. Cyclic AMP also needs to be decreased in the treatment of cancer because it is an immune system depressant. So, there are many good things about the sun, if the atmosphere doesn't get too bad! Mary Jackson