No, this blog title is not a sign that I have gone insane (there is plenty of other evidence of that).

I’m currently in Japan. I know it’s 420 but marijuana is a serious offence here. The Hakone Kowakien Yunessun, however, is a nifty bath house with baths of upper and downer beverages of your choice: coffee, green tea, sake, and red wine. Located about an hour by train outside of Tokyo, the pools are a little gimmicky but the rest of the joint (teehee see what I did there?) is an awesome waterpark-spa-onsen hybrid, where you can be slow-cooked outdoors to a perfectly tender 41.4°C.

 

My favourite of the four beverage baths were definitely the coffee and green tea ones, mostly because of the scents. Speaking of these beverages, have you ever thought about how caffeine works in our body to boost our alertness? Adenosine is a neurochemical. When it binds to the right receptors in our brain, it suppresses arousal and promotes sleep. Think of the brain as a big parking lot, the receptors as parking spaces, and adenosine as cars. When all the spots are filled up by cars, an attendant checks and sees that the lot is full and shuts off the “space available” sign. In the body, this is sort of like getting the signal to sleep. Now think of caffeine as a bunch of orange plastic pylons that someone has put in every parking spot in place of the cars. All the spots are now occupied, so cars driving into the lot cannot find spaces to park in. Meanwhile, the attendant comes to check on the lot and sees that there are lots of cars circling, but there is no way he can instantly make all the pylons disappear, nor can he turn off that “space available” sign. So the cars (the adenosine) are just left to circle the lot and without the change of sign, the body does not get the signal to sleep. But the pylons (caffeine) can’t just occupy the spots (adenosine receptors) forever, just as we cannot depend on caffeine to stay alert indefinitely. The attendant starts to clear them out, and the cars, annoyed to have had to circle the lot (unbound adenosine floating in the brain), make a beeline for every spot as soon as they open (adenosine binding to the now-vacant receptors). When the cars finally fill back up their rightful spots again, the attendant can then turn off the “space available” sign. In the body, this is the equivalent of a caffeine crash.

Where this analogy falls off is how our body adapts. Whereas new parking spots don’t automatically get created because they were blocked up by pylons, we actually grows more adenosine receptors if it senses that there is often a lot of excess adenosine just kicking around. This is why, over time, we need to drink more and more coffee just to retain a similar level of alertness.

Have I bored you to death with this explanation? Do you need a caffeine jolt to perk up?

 

receptor binding.