Meeting Abstract

61.4  Friday, Jan. 6  Chronic Hypoxic Incubation Stress and the Plasticity of Humoral Regulation of cardiovascular function in the American alligator (Alligator mississippiensis) TATE, KB*; SLAY, CE; HICKS, JW; CROSSLEY II, DA; U N Texas; U C Irvine; U C Irvine; U N Texas

The stress conditions of the incubation environment can impact an in ovo developing embryo. One natural stressor for developing reptiles is reduced micro-environmental oxygen content (hypoxia). Hypoxia has been documented in embryos of the American alligator (Alligator mississippiensis) to alter the capacity for reflexive regulatory system suggesting plasticity. However, the plasticity of humoral regulatory systems in response to developmental hypoxia is unknown. In this study we assessed the response of known adult humoral regulators arginine vasotocin (AVT), adenosine (ADO) and endothelin-1 (ET-1) in embryos incubated chronically in 10% O2 (H-10) and 21% O2 (N-21). H-10 embryos were markedly smaller, hypertensive, and bradycardic compared to N-21 embryos. Injection of AVT (through a tertiary chorioallantoic artery) induced an immediate hypertensive response in both H-10 and N-21 embryos, concurrent with a bradycardia. ADO injection resulted in a brief hypotensive bradycardia, in both H-10 and N-21 groups. Injection of ET-1 failed to induce a response, in either H-10 or N-21 embryos. The data suggest that, as demonstrated in adult vertebrates, AVT and ADO are vasoactive components, and appear to be involved in the cardiovascular regulation in embryonic alligators. NSF CAREER IBN IOS-0845741 to DAC