Dr. David Saunders

Coagulation Mechanisms in Hibernating Reptiles and Amphibians

My research lab is interested in the blood clotting mechanisms in reptiles and amphibians. These animals are ectothermic in that their body temperatures are very similar to the temperature of the environment that surrounds them. Blood clotting is temperature dependent in endotherms (mammals and birds), with an increase in the time it takes to develop a blood clot occurring with decreasing temperature. However, little is known about the effects of temperature clotting in ectotherms. Further, ectotherms may have body temperatures that will be close to freezing during hibernation, temperatures birds and mammals never experience. As such, they may have different mechanisms that control clotting.

The Effect of Red Blood Cell Size on Red Blood Cell Strength

Red blood cell (erythrocyte) strength can be measured by determining point at which the cell will lyse (break apart) when exposed to osmotic stress. Previous research from my lab has shown that larger red blood cells, like those that occur in reptiles and amphibians, are more resistant to lysing than are smaller red blood cells found in birds and mammals. We are now looking into the mechanisms that might play a role in the strength of larger red blood cells. These include the role of ion channels in regulatory volume decrease, and potential structural components of the cell membrane of larger red blood cells.