Meeting Abstract

P1.117  Sunday, Jan. 4  Chorioallantoic Membrane Vascular Function of the Embryonic Domestic Chicken (Gallus gallus) ALVINE, T*; CROSSLEY II, DA; University of North Dakota; University of North Dakota travis.alvine@und.edu

Vascular function and regulation is poorly understood in most fetal/embryonic vertebrates. Given the complexity of the vascular tree in developing animals, specifically the presence of the chorioallantoic membrane (CAM) vascular bed, a thorough investigation of vascular function must be completed. The CAM vasculature is critical as a gas exchange surface, and thus changes in vascular resistance will have direct effects on convective gas transport. To characterize CAM vasculature function, an isolated embryonic chicken CAM perfusion preparation was used. This model is particularly useful because it eliminates potential fetal-maternal physiological interactions. Eggs of the domestic chicken (Gallus gallus) incubated at 38C were selected for study at days 15 and 19 of the developmental period, days corresponding to maximal CAM development and the period just prior to lung ventilation, respectively. On the day of study, the CAM vascular tree was isolated from euthanized embryos, and the major CAM artery was occlusively catherized. The preparation was perfused with saline (0.9% NaCl) at rates that mimicked previously published blood flow rates on these days of development. Responses of CAM vascular function were studied via pharmacological manipulation with selective receptor agonists, phenylephrine (alpha-adrenergic), isoprenaline (beta-adrenergic), and Angiotensin II. Preliminary data indicate that the embryonic chicken CAM responds to both beta and alpha-adrenergic receptor stimulation at day 15 and 19. These data, in combination with molecular in situ hybridization used to localize receptor mRNA, imply regulation of CAM vascular resistance may be an important mechanism of altering cardiovascular function in embryonic birds.