Meeting Abstract

P3.6  Saturday, Jan. 5  Cardiovascular Control Mechanisms Present at Two Points of Development in Embryonic Common Snapping Turtles (Chelydra serpentina). ALVINE, Travis D.*; CROSSLEY, Dane A.; Univ. of North Dakota; Univ. of North Dakota travis.alvine@und.nodak.edu

Physiological studies in reptiles have classically focused on the juvenile or adult phase of life. While these studies have been critical to expanding our knowledge of physiology in this group, our understanding of its maturation in embryonic reptiles is limited. This is particularly true of cardiovascular physiology in developing reptiles in which extensive studies have been completed in the American alligator. Therefore this study was undertaken to expand our knowledge of embryonic cardiovascular physiology in reptiles. In addition, the degree to which patterns of physiological development in the American alligator apply to other developing reptilian species was determined. Eggs of the common snapping turtle (Chelydra serpentina) incubated at 26 degrees C were selected for study at 75% and 90% of incubation. Following surgical instrumentation an assessment of cardiovascular control mechanisms was conducted via selective receptor antagonist (atropine, propranolol, and phentolamine). Baseline mean arterial pressure (Pm) increased from 0.6 kPa to 1.2 kPa while heart rate (fH) decreased from 58�2 min-1 to 43�3 min-1 over the period of study. Cholinergic tone on the cardiovascular systems was present during the period of study. In addition, both β and α adrenergic tones were present during incubation, with embryos possessing a β stimulatory tone on heart rate and a α stimulatory tone on pressure. Collectively the data indicate that changes in cardiovascular regulation occur during this period of embryonic development in snapping turtle. In addition, there are important differences from our current understanding of this process in American alligators during incubation.