QUICK SEARCH:   [advanced] Author: Keyword(s):
Home     Help     Feedback     Subscriptions     Archive     Search     Table of Contents

First published online October 27, 2003

This Article Figures Only Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Related articles in JEB Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Wang, T. Articles by Axelsson, M. Search for Related Content PubMed PubMed Citation Articles by Wang, T. Articles by Axelsson, M.

The Journal of Experimental Biology 206, 4241-4245 (2003)
doi: 10.1242/jeb.00681

Ventricular haemodynamics in Python molurus: separation of pulmonary and systemic pressures

Tobias Wang^1,*, Jordi Altimiras², Wilfried Klein³ and Michael Axelsson⁴

¹ Department of Zoophysiology, University of Aarhus, 8000 Aarhus C, Denmark,
² Department of Biology, IFM, University of Linköping, Sweden,
³ Institute of Zoology, University of Bonn, Germany
⁴ Department of Zoology, University of Gothenburg, Sweden

^* Author for correspondence (e-mail: tobias.wang{at}biology.au.dk)

Accepted 20 August 2003

Vascular pressure separation by virtue of a two-chambered ventricle evolved independently in mammals and birds from a reptilian ancestor with a single ventricle, and allowed for high systemic perfusion pressure while protecting the lungs from oedema. Within non-crocodilian reptiles, ventricular pressure separation has only been observed in varanid lizards and has been regarded as a unique adaptation to an active predatory life style and high metabolic rate. The systemic and pulmonary sides of the ventricle in Python molurus are well separated by the muscular ridge, and a previous study using in situ perfusion of the heart revealed a remarkable flow separation and showed that the systemic side can sustain higher output pressures than the pulmonary side. Here we extend these observations by showing that systemic blood pressure P_sys exceeded pulmonary pressure P_pul almost seven times (75.7±4.2 versus 11.6±1.1 cm H₂O). The large pressure difference between the systemic and pulmonary circulation persisted when P_sys was altered by infusion of sodium nitroprusside or phenylephrine. Intraventricular pressures, measured in anaesthetised snakes, showed an overlap in the pressure profile between the pulmonary side of the ventricle (cavum pulmonale) and the pulmonary artery, while the higher pressure in the systemic side of the ventricle (cavum arteriosum) overlapped with the pressure in the right aortic arch. This verifies that the pressure differences originate within the ventricle, indicating that the large muscular ridge separates the ventricle during cardiac contraction.

Key words: Reptile, snake, Python molurus, cardiovascular, blood pressure, ventricular pressure, vascular pressure separation.

Related articles in JEB:

PYTHONS KEEP THE PRESSURE UP

Kathryn Phillips
JEB 2003 206: 4182. [Full Text]  

This article has been cited by other articles:

				J. S. Torday, V. K. Rehan, J. W. Hicks, T. Wang, J. Maina, E. R. Weibel, C. C.W. Hsia, R. J. Sommer, and S. F. Perry Deconvoluting lung evolution: from phenotypes to gene regulatory networks Integr. Comp. Biol., October 1, 2007; 47(4): 601 - 609. [Abstract] [Full Text] [PDF]

				G. L. J. Galli, H. Gesser, E. W. Taylor, H. A. Shiels, and T. Wang The role of the sarcoplasmic reticulum in the generation of high heart rates and blood pressures in reptiles J. Exp. Biol., May 15, 2006; 209(10): 1956 - 1963. [Abstract] [Full Text] [PDF]

				K. Phillips PYTHONS KEEP THE PRESSURE UP J. Exp. Biol., December 1, 2003; 206(23): 4182 - 4182. [Full Text] [PDF]