This post was originally published on April 09, 2006.

This April 09, 2006 post places another paper from my old lab (Reference #17) within a broader context of physiology, behavior, ecology and evolution. The paper was a result of a communal experiment in the lab, i.e., it was not included in anyones Thesis. My advisor designed it and started the experiment with the first couple of birds. When I joined the lab, I did the experiment in an additional number of animals. When Chris Steele joined the lab, he took over the project and did the rest of the lab work, including bringing in the idea for an additional experiment that was included, and some of the analysis. We all talked about it in our lab meetings for a long time. In the end, the boss did most of the analysis and all of the writing, so the order of authors faithfully reflects the relative contributions to the work.

What is not mentioned in the post below is an additional observation that return of the food after the fasting period induced a phase-shift of the circadian system, so we also generated a Phase-Response Curve, suggesting that food-entrainable pacemaker in quail is, unlike in mammals, not separate from the light-entrainable system.

Finally, at the end of the post, I show some unpublished data a rare event in science blogging.

If you know what Chossats Effect is, I guess you are a) a physiologist, b) expert in thermoregulation, and c) old. This is term that got expunged from the scientific lexicon a few decades ago, in an effort correct me if I am wrong on this spearheaded by the U.S. textbook companies, to replace scientific terminology named after the discoverers (and sometimes even Latin and Greek terms) with bland English neologisms.

But I love Schwanns Cells, Fallopian Tubes (or Mullerian Ducts), Purkinje Fibers, Broccas Area and the amazing Bundle of His! Those terms are memorable, make it easy to sneak in some historical context into teaching science, and have an emotional effect of bringing forth images of ancient scientists working under candlelight, sacrificing their eyesight and health, their social standing and sometimes even their lives, in the feverish hunger for knowledge.

So, what is Chossats Effect? It comes from a 19th century French scientist who was studying the physiology of starvation [1]. The modern term for this effect is fasting-induced nocturnal hypothermia (doesnt that sound like something that would prompt the students in the classroom to immediatelly stop paying attention to the teacher and instead pick-up their cell-phones and start text-messaging their friends?).

Actually, this is a very interesting area of research that is very tightly connected to circadian biology. This post is likely to be long, so feel free to skim and just focus on the first part if you are into birds, second part if you are interested in mammals, and the last part if you are into humans.

Birds

All warm-blooded animals (and yes, that includes at least some reptiles, not to mention a few heat-producing plants like stink-cabbage) exhibit a daily rhythm of body temperature. If an animal is active during the day (diurnal) and sleeps during the night, reducing the metabolic rate during the night is a good way to save energy.

Follow this link:
Chossat's Effect in humans and other animals