A “Hearty” Eater
Big Meals Condition a Snake’s Heart
A Burmese python is strong, but is it a model for human exercise? According an article published in the March 3 issue of the journal Nature, the snake’s eating habits make it a prime model of cardiovascular fitness. The heart has the amazing ability to adapt to altered physiological requirements, and, according to the authors, this cold-blooded snake may provide insights into how remodeling of the heart occurs in adapting to prolonged exercise and in response to some diseases.
The python does not eat frequently; it’s more of a binge eater. James Hicks at the University of California, Irvine, together with his colleagues, discovered the snake's tell-tale heart undergoes drastic physiological changes after the reptile consumes a large meal. Hicks observed that the snake’s oxygen consumption increased seven-fold within 24 to 48 hours after eating. This heightened metabolic state lasted for up to seven days and was accompanied by a rapid remodeling of the ventricle--the lower portion of the blood-pumping organ. In experiments, the python’s ventricle increased in mass by 40 percent within 48 hours.
Unlike a human heart, which has two ventricles or pumping chambers, a reptile heart has only one.
“In mammals, including humans, a 10-30 percent increase in ventricular mass can occur following several weeks to months of intense aerobic training,” said Hicks.
In the snake, the rapid ventricular growth coincided with an increased production of the muscle protein, myosin. Myosin is involved in muscle contraction, and hence, plays a key role in pumping blood.
Hicks and his colleagues propose that these animals could be an informative model for investigating fundamental mechanisms leading to cardiac remodeling and ventricular growth in other animals, including humans.
Hicks’ research is supported by the Integrative Organismal Biology program at the National Science Foundation.
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