Meeting Abstract

P2.102  Jan. 5  Cardiovascular response to digestion and exercise in the Burmese python SECOR, S.M.*; WHITE, S.E.; University of Alabama; Tidmore Veterinary Hospital ssecor@biology.as.ua.edu

Python digestion and exercise is accompanied by large increases in metabolic rate and cardiac output. Predictably, blood flow to the python�s GI tract increases with feeding to support the upregulation of gastric and intestinal performance, whereas during exercise, blood is shunted away from the gut to support locomotory muscles. However, if faced with both demands (digestion and exercise), how will blood then be allocated? To explore for the Burmese python the preferential shunting of blood during digestion, exercise, and exercising while digesting, we surgically implanted perivascular blood flow probes around a carotid artery, the dorsal aorta, superior mesenteric artery, and hepatic portal vein of six adult pythons (mean = 11.8 kg). We measured blood flow of snakes fasted and rested, fasted and exercising, during the digestion of a meal 25% of body mass, and exercising five days after feeding (still digesting). For fasted snakes, exercise generated respective 3.4-, 1.9-, and 2.8-fold increases in cardiac output, hepatic portal flow, and heart rate, and a 67% decrease in superior mesenteric blood flow. During digestion, cardiac output and heart rate peaked at 4.6- and 3.4-fold of resting, as blood flow through the superior mesenteric artery and hepatic portal vein increased by 11.3- and 16.7-fold. When digesting snakes are forced to exercise they experience 15% to 25% increases in cardiac output and heart rate over exercise or digesting rates. At the same time these snakes experience 80% and 47% decreases in blood flow through the superior mesenteric artery and hepatic portal vein. While the combination of digestion and exercise has additive impact on cardiac performance, blood is preferentially shunted away from the gut with exercise to support skeletal muscle activity.