Too tired to be witty

Okay, friends. Why am I so exhausted? It’s prob­ably just the rain or maybe I’m get­ting sick. But what if my cir­ca­dian rhythms are off!? Biology pro­fessor Fred Davis pre­sented his work in just that sub­ject last week as part of an inter­dis­ci­pli­nary panel hosted by the Col­lege of Sci­ence to drum up interest in stu­dent research opportunities.

I swear I’m not just pre­tending to be tired for the pur­poses of this blog post. I really am inex­plic­ably exhausted — I’ve been get­ting oodles of sleep lately! So when I was thinking of what to write about today, Davis’ work spon­ta­neously popped into my head. I wish life were always that serendipitous.

Anyway, cir­ca­dian rhythms are bio­log­ical processes that nat­u­rally follow a 24 hour cycle.  “Cycles of light and tem­per­a­ture have had a pro­found effect on the evo­lu­tion of life,” Davis said. “Having evolved on a rotating planet gave advan­tages to having a 24 hour internal clock to antic­i­pate changes in the environment.”

This so-​​called clock was first detected in 1729, when botanists observed the move­ment of plant leaves over night and day. In 1938 sci­en­tists set up the first cir­ca­dian rhythm exper­i­ment with humans. Sub­jects lived in Mam­moth Cave in Ken­tucky for extended periods of time with no expo­sure to nat­ural light. They had con­trol over their own syn­thetic light sources and without knowing it, main­tained their 24 hour day just as if they were living a normal life.

In today’s exper­i­ments, lab ani­mals are kept under con­stant con­di­tions (always light, always dark) and find that their 24 hour behav­ioral pat­terns per­sist. The clock was found to reside in the suprachi­as­matic nucleus (SCN) in the hypo­thal­amus, Davis said, which is where the neu­rons from the eye enter the brain.

You can impair the SCN of a ham­ster so that his cir­ca­dian rhythms are all messed up — you know, run­ning on the  ham­ster wheel at all hours of the day or night. But if you trans­plant a healthy SCN into these guys, their rhythms are com­pletely restored.

In addi­tion to the SCN, research has shown that every cell in the body con­tains its own mini-​​clock. Davis’ is now focusing his work in this area, per­forming stem cell trans­plants in mice to try and restore func­tion when the rhythms are dysfunctional.

Since people with Alzheimer’s dis­ease tend to have sig­nif­i­cant prob­lems with their rhythms, Davis said, this kind of work could be very ben­e­fi­cial to human patients.

While I’m pretty sure my exhaus­tion has nothing to do with wonky cir­ca­dian rhythms, I am writing this from a win­dow­less office ;)