AJP - Regulatory, Integrative and Comparative Physiology, Vol 256, Issue 1 240-R247, Copyright © 1989 by American Physiological Society

ARTICLES

Relationship between respiratory state and intracardiac shunts in turtles

F. N. White, J. W. Hicks and A. Ishimatsu
Max-Planck-Institut fur Experimentelle Medizin, Abteilung Physiologie, Gottingen, Federal Republic of Germany.

Injection of radioactively labeled microspheres and blood O2 analysis from central vascular sites was utilized to assess intracardiac shunts in the unanesthetized and unrestrained turtle, Pseudemys scripta, at 15 degrees C. Both methods indicated a simultaneously occurring right-to-left (R-L) and left-to-right (L-R) shunt during ventilation and apnea. During ventilation, the O2 method estimated a R-L shunt of 24%. In contrast, injection of microspheres during ventilation estimated a R-L shunt of 65%, which was significantly greater than the value determined from the O2 method. During apnea, both methods indicated a significantly larger R-L shunt. Estimates of the R-L shunt from O2 analysis were between 60 and 90% of the venous return. The R-L shunt estimated from the O2 content of left aortic arch blood was significantly greater than the value determined from right aortic arch blood. During apnea, the microsphere method estimated a R-L shunt of 79%, which was in the intermediate range calculated by the O2 method using two aortic arches. Our results verify previous reports of significant differences in R-L shunt levels between ventilation and apnea during the normal ventilatory cycle of turtles.

This article has been cited by other articles:

				J. Overgaard, J. A. W. Stecyk, A. P. Farrell, and T. Wang Adrenergic control of the cardiovascular system in the turtle Trachemys scripta J. Exp. Biol., November 1, 2002; 205(21): 3335 - 3345. [Abstract] [Full Text] [PDF]

				B. Platzack, Y. Wang, D. Crossley, V. Lance, J. W. Hicks, and J. M. Conlon Characterization and cardiovascular actions of endothelin-1 and endothelin-3 from the American alligator Am J Physiol Regulatory Integrative Comp Physiol, February 1, 2002; 282(2): R594 - R602. [Abstract] [Full Text] [PDF]

				B. Platzack and J. W. Hicks Reductions in systemic oxygen delivery induce a hypometabolic state in the turtle Trachemys scripta Am J Physiol Regulatory Integrative Comp Physiol, October 1, 2001; 281(4): R1295 - R1301. [Abstract] [Full Text] [PDF]

				J. W. Hicks and T. Wang Hypoxic hypometabolism in the anesthetized turtle, Trachemys scripta Am J Physiol Regulatory Integrative Comp Physiol, July 1, 1999; 277(1): R18 - R23. [Abstract] [Full Text] [PDF]