Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

In anoxia, why can’t humans be more like western painted turtles?

04.04.2005


The right answer could yield better anesthetics, as well as improved stroke and heart attack outcomes – for everyone



For a human, mere minutes without oxygen (called anoxia) resulting from cardiac arrest, cerebral stroke or being trapped under water can lead to profound tissue damage and even death. However a Western painted turtle can survive anoxia for months without apparent tissue damage. Why, and how?

"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 35th Congress of the International Union of Physiological Sciences in San Diego, March 31 - April 5, 2005.

New potassium channel blockage short-circuits turtle’s shutoff mechanism

A known protective factor is adenosine, a compound that accumulates in both mammalian and reptile (turtle) brains in response to low oxygen levels. It reduces the inflow of calcium through NMDA receptors during anoxia and is associated with brain protection. "However, our work suggests that adenosine isn’t the only protective factor. Even with the adenosine pathways inhibited, calcium influx in anoxic turtle brain still decreases," Buck noted.

Mathew Pamenter, a graduate student in the lab, had the idea to investigate a relatively newly discovered potassium channel (mitochondrial KATP channel) as a possible regulator of NMDA receptor activity during anoxia. "When this new channel was inhibited, the protective decrease in calcium influx previously observed in anoxic turtle brain didn’t occur," Buck said. "This result indicates that this channel plays a key role in the natural anoxia-tolerance of the turtle and opens a new research direction in this area."

Next steps. Buck said one avenue of investigation is to see whether the potassium channels may be part of an oxygen sensing mechanism, which some believe. "Our ultimate goal is to determine the natural cellular pathways responsible for oxygen sensing and the shutting off of energy consuming processes in the turtle," Buck said. "Then I want to apply this knowledge to human clinical situations, such as improving outcomes of cerebral stroke and cardiac infarct, and the development of better anesthetics."

Mayer Resnick | EurekAlert!
Further information:
http://www.the-aps.org

More articles from Health and Medicine:

nachricht Finnish research group discovers a new immune system regulator
23.02.2018 | University of Turku

nachricht Minimising risks of transplants
22.02.2018 | Friedrich-Alexander-Universität Erlangen-Nürnberg

All articles from Health and Medicine >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Attoseconds break into atomic interior

A newly developed laser technology has enabled physicists in the Laboratory for Attosecond Physics (jointly run by LMU Munich and the Max Planck Institute of Quantum Optics) to generate attosecond bursts of high-energy photons of unprecedented intensity. This has made it possible to observe the interaction of multiple photons in a single such pulse with electrons in the inner orbital shell of an atom.

In order to observe the ultrafast electron motion in the inner shells of atoms with short light pulses, the pulses must not only be ultrashort, but very...

Im Focus: Good vibrations feel the force

A group of researchers led by Andrea Cavalleri at the Max Planck Institute for Structure and Dynamics of Matter (MPSD) in Hamburg has demonstrated a new method enabling precise measurements of the interatomic forces that hold crystalline solids together. The paper Probing the Interatomic Potential of Solids by Strong-Field Nonlinear Phononics, published online in Nature, explains how a terahertz-frequency laser pulse can drive very large deformations of the crystal.

By measuring the highly unusual atomic trajectories under extreme electromagnetic transients, the MPSD group could reconstruct how rigid the atomic bonds are...

Im Focus: Developing reliable quantum computers

International research team makes important step on the path to solving certification problems

Quantum computers may one day solve algorithmic problems which even the biggest supercomputers today can’t manage. But how do you test a quantum computer to...

Im Focus: In best circles: First integrated circuit from self-assembled polymer

For the first time, a team of researchers at the Max-Planck Institute (MPI) for Polymer Research in Mainz, Germany, has succeeded in making an integrated circuit (IC) from just a monolayer of a semiconducting polymer via a bottom-up, self-assembly approach.

In the self-assembly process, the semiconducting polymer arranges itself into an ordered monolayer in a transistor. The transistors are binary switches used...

Im Focus: Demonstration of a single molecule piezoelectric effect

Breakthrough provides a new concept of the design of molecular motors, sensors and electricity generators at nanoscale

Researchers from the Institute of Organic Chemistry and Biochemistry of the CAS (IOCB Prague), Institute of Physics of the CAS (IP CAS) and Palacký University...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

2nd International Conference on High Temperature Shape Memory Alloys (HTSMAs)

15.02.2018 | Event News

Aachen DC Grid Summit 2018

13.02.2018 | Event News

How Global Climate Policy Can Learn from the Energy Transition

12.02.2018 | Event News

 
Latest News

Basque researchers turn light upside down

23.02.2018 | Physics and Astronomy

Finnish research group discovers a new immune system regulator

23.02.2018 | Health and Medicine

Attoseconds break into atomic interior

23.02.2018 | Physics and Astronomy

VideoLinks
Science & Research
Overview of more VideoLinks >>>