The cardiovascular system is the first organ system to function in vertebrate embryos, and as such is critical to the development of all subsequent tissues and organs. Yet, the development of embryonic cardiovascular physiology remains very poorly understood for any vertebrate, including birds and mammals. This project will investigate the development of cardiovascular physiology in amphibian larvae, which are highly appropriate as a model for vertebrate embryos in general. Measurements will be made of heart rate, cardiac output, blood pressure and peripheral resistance. The experiments will be designed to determine the onset of, and subsequent developmental changes in, the basic heart functions (heart rate, arterial blood pressure, cardiac output, peripheral resistance) of the immediate post-hatch anuran larva. Once basic hemodynamics have been measured, then the development of the ability of the heart to regulate its own function will be described. This study will be the first comprehensive investigation of the development of cardiovascular function in any lower vertebrate. Amphibian development traditionally has served as a general model for vertebrate development, and consequently the physiological studies will have broad applicability to both vertebrate physiology and developmental biology, particular in the absence of substantial published data on either bird or mammal embryos.
