STARCK, J.M.; WIMMER, C.; GENSLER, H.; Univ. of Munich, Germany; Univ. of Munich, Germany; Univ. of Munich, Germany: Patterns of Blood flow in Feeding and Fasting Pythons. A Duplex-Ultrasonography Study

The post-feeding response of pythons has been characterized frequently. We have quantitatively studied the patterns of blood flow, i.e., blood flow velocity and blood volume delivered to different organ systems. Blood flow volume takes a functional key position in the postprandial response because it delivers oxygen and fuel to the organs that have increased in size and transports nutrients that have been absorbed from the small intestine to the liver. We applied a fully non-invasive Duplex-ultrasonography technique to study changes in blood flow velocity and blood flow volume delivered to the small intestine and liver during feeding and fasting. We used an Esaote Technos MP ultrasound machine equipped with a 8-14 MHz linear scanner head for imaging. Duplex sonographs were taken at 10 MHz and a pulse repetition frequency of 120 Hz. We measured cardiac output, blood flow velocity and blood flow volume in the mesenteric artery, the liver portal vein and the liver vein. Synchronized with the duplex ultrasonography we recorded the electrocardiogram of the snakes. Five snakes were studied; first during fasting and then for two weeks after feeding. Measurements were taken daily. We observed significant changes in all measured parameters, i.e., blood flow volume to the gastrointestinal tract and the liver increased immediately after feeding. Interestingly, the pattern of blood flow changed on the hepatic portal vein from typical venous pattern (i.e., continuous flow) during fasting to arterial pattern (pulsed flow) after feeding. As a methodical side aspect we point out that duplex ultrasonography offers straightforward, fully noninvasive, and quantitative information about blood flow volume and velocity under different physiological conditions even in small vertebrates.