David H. Evans, Ph.D.
 |
Visiting Faculty, University of Florida
Membrane Biology
Environmental Stress Biology
B.A., DePauw University, Zoology, 1962
Ph.D., Stanford University, Biology, 1967
We are interested in the physiology of the fish gill; specifically, how control of blood flow to the gill and epithelial transport mediate such important functions as osmoregulation, nitrogen excretion, acid-base regulation, and gas transport. Most recently, we have been investigating the role(s) of signaling agents such as endothelin, nitric oxide, prostaglandins, urotensin, and vasotocin in the control of gill perfusion and ion transport. In our studies, we have utilized a variety of fish species including dogfish shark, hagfish, lamprey, eel, killifish, and sculpin.
Paracrine Control of Fish Gill Function
Since the diameter of blood vessels can control blood pressure and flow, there is considerable interest in the role of various substances in controlling the contraction vs. dilation of blood vessels in vertebrates, especially humans and other mammals. In fishes, the control of blood flow to the gills can affect important functions of the gills including gas exchange, osmoregulation, nitrogen excretion, and acid-base balance. Our interests center around the role of various substances (endothelin, nitric oxide, prostaglandins, and natriuretic peptides) that may affect the perfusion of the gills as well as active salt secretion. Our studies use physiological, pharamacological, and some molecular techniques.