This project is directed at understanding the function and control of the heart and vascular systems of vertebrates during the early stages of development. The heart is one of the first organs to form and assume its adult function, yet it does so long before the developing nervous system can reach it. This project will help define the ability of the nascent cardiovascular system to regulate itself without the assistance of the nervous system. It is suspected that the blood vessels themselves may provide the key to regulation during these very early stages of development. Research in this area is hampered by the minute size of vertebrate embryos and larvae, and only recently has it been technologically possible to determine blood pressure and blood flow in embryos and larvae. The question of blood pressure regulation is especially interesting in light of the knowledge that the cardiovascular system is responsive to the pressures and flows it generates and is capable of remodeling in response to increased or decreased pressure. Thus, maintaining appropriate pressures and flows during development may be critical for appropriate cardiovascular morphology to appear. Abnormal pressures or flows may result in pathological abnormalities, but may also account for the ability of heart shape and vascular geometry to evolve in such a fashion as to support the widely varying lifestyles of the vertebrates. The research proposed herein, will also involve training a large number of students from high school to graduate level at New Mexico State University. This is especially valuable in this locale given our high density of underrepresented minority students. This research will serve as a training ground to provide "hand on" research experience to these students.