The central circulation in the lizard Tupinambis teguixin (Linné 1758) was studied using angiocardiographic techniques. Contrast medium was selectively injected into the vena cava superior, the sinus venosus, the right atrium, and the ventricular subcompartments [the cavum pulmonale (CP) and cavum arteriosum (CA)], following catheterization of the heart from the right jugular vein.
Contrast medium injection in the vena cava, sinus venosus, right atrium or CP showed that there was an exclusive and selective passage to the pulmonary circulation when injections were made during spontaneous or artificial ventilation. Contrast injection during apnoea showed various degrees of right-left shunting to the left aorta but typically not to the right aorta. There was no observable admixture from the CP to the CA.
When contrast medium was injected directly into the cavum arteriosum, there was clear selective filling of the right aorta and the cephalad circulation, as well as a lesser but distinct filling of the left aorta. During systole, there was no admixture from the CA to the CP, but a very slight left-right admixture was discernible during ventricular diastole.
The selective passage of contrast medium through the heart of Tupinambis showed a relationship to breathing in the intermittent ventilation pattern of Tupinambis. During apnoea, pulmonary flow appears to be impeded: this may reflect right-left shunting to the left aorta. This vessel becomes important in the alternation between a balance of pulmonary and systemic flow during breathing and a preference for systemic flow during apnoea.
I am sorry to inform the readers of this journal and the whole scientific world that the famous Professor Kjell Johansen suddenly passed away during a sojourn in France for purposes of study. We will all miss a dear friend and colleague.
Reprint requests should be sent to Dr J. H. Andresen, Department of Diagnostic Radiology, Municipal Hospital of Aarhus, DK-800 Aarhus C, Denmark.