This research will examine the physiological control of blood flow through the blood vessels in the fish gill, as well as the control of salt transport across the cells in the gill tissue. The gill is the major site of gas exchange, salt and water regulation, excretion of nitrogenous wastes, and regulation of blood pH. This study of regulation can provide important clues to a variety of physiological processes in fish, and vertebrates in general. Research will continue to investigate the role(s) of the local signaling agents (termed paracrines) such as endothelin (ET), nitric oxide (NO), superoxide ion (SO), and prostaglandins (PGs), in gill function. Current evidence suggests that all of these agents can alter blood flow through gill vessels, as well as salt transport across the gill tissue. Moreover, it appears that these agents may be members of a signaling cascade whereby (for instance) ET produces its effects via the production of PGs. The investigators will use a variety of physiological, immunological, and molecular techniques to determine the effects of these signaling agents and study their interactions under the conditions of salinity change. Unique training opportunities will occur for graduate and undergraduate students on this research in a wide range of physiological techniques including time spent at the Mount Desert Island Biological Laboratory. This research will increase our knowledge of basic biology in fishes and will provide information about the evolution of these cellular signaling mechanisms in the evolution of the vertebrates.
