"Key to surviving anoxia is the shutting off of energy-utilizing cellular activities, such as the synthesis of proteins and perhaps most importantly reducing the activity of energy intensive ion pumps," according to Leslie T. Buck, a physiologist at University of Toronto's Zoology Department. Whereas turtles and many other animals have shutoff mechanisms, humans and many mammals don't.
"However, basic biochemical pathways are common to almost all species, certainly among reptiles (turtles), fish, birds and mammals," Buck said, adding: "Therefore, the basic signals and pathways that permit anoxia-tolerance in the turtle must also be present in mammals."
In studying the natural mechanisms of anoxia tolerance, Buck's lab focused on a particular ion channel, the N-methyl-D-aspartate (NMDA) receptor. This receptor/channel is strongly associated with anoxic damage in the mammalian brain by permitting a very large flow of calcium ions into the cell during anoxia. Unlike anoxia-sensitive mammals, this doesn't occur in the western painted turtle's brain.
*Paper presentation: "NMDA receptor regulation by mitochondrial KATP channels and adenosine receptors in cortical neurons of the anoxia-tolerant western painted turtle," 12:30 p.m.-3 p.m. Sunday April 3, Physiology 381.3/board #A558. On view 7:30 a.m. - 4 p.m. Others in the research team are Damian Shin and Matthew Pamenter.
Featured topic: Buck is also participating in "Mechanisms of metabolic depression: comparative aspects," Sunday April 3, room 30 B/C beginning at 10:30 a.m. His presentation is scheduled for noon.
Buck is presenting the research at the 3