Hacker Newsnew | past | comments | ask | show | jobs | submitlogin

This is incorrect information. (... Like so many biology/chemistry comments I see on HN.)

Caffeine is more like an adenine analog, not a cAMP (3'-5' cyclic adenosine monophosphate) analog. It binds adenosine receptors, not primarily cAMP receptors. It has indirect effects on cAMP, but I am not aware of direct ones. Also, your description of cAMP signaling sounds confused, since cAMP is an intracellular second messenger. I am not aware of an extracellular retrograde signaling process for this molecule.

Sorry, and your implication that cAMP is a byproduct of ATP consumption is totally wrong. cAMP is synthesized directly from ATP, a reaction catalyzed by the regulated enzyme adenylate cyclase.



Thank you for the correction. I mis-remembered a minor detail from a lecture that was 9 years ago, and have find/replaced cAMP -> adenosine in the above post. The gist of the post, though, remains the same. That is, caffeine competitively inhibits receptors that gate ion channels, and the mechanism of tolerance is an increase in the concentration of the thing that it competitively binds.

(My thesis was on auditory cognition and I haven't touched ion channel biophysics in that long. I have a long-ago memory that adenosine (now corrected) operated as a retrograde transmitter, though since I'm probably not going to spend my afternoon looking for the citations, I'll delete as well for now. Not because I believe it's wrong, just that I can't immediately back it up.)

Are you still doing research yourself or have you left for startup land like most of HN?


Thanks for making your corrections as well. Yes, I am in research, and I mostly come here for what's new in Python, learning algorithms, and data analysis. As an aside, it's tough to wade through the "startup land" and personal health advice and keep a straight face in all honesty, but there are few other places that aggregate the things I'm interested in on the computing side of things. An "HN" with users that specialize in bioscience would be very interesting, but I don't know of one with any level of seriousness/activity.


datatau [0] might be worth checking out, if you're not familiar.

since bioscience isn't on my radar i'm not sure if you'd find anything useful there, however, it feels like a more concentrated version of HN which specializes in some of the other stuff that interests you (e.g. learning algos, data analysis, etc.).

[0] http://www.datatau.com/


This source (http://udel.edu/~danikoll/metabolism.html) validates your point that caffeine has an indirect rather than direct effect on cAMP:

"Caffeine competitively inhibits phosphodiesterase, the enzyme that degrades cyclic AMP...By blocking the degradation process of cyclic AMP, caffeine indirectly affects regulation of cAMP-dependent protein kinases". TIL.




Guidelines | FAQ | Lists | API | Security | Legal | Apply to YC | Contact

Search: