As for most ectothermic vertebrates, the breathing pattern of turtles is episodic, and pulmonary blood flow (Qpul) and heart rate (fH) normally increase several-fold during spontaneous ventilation. While some previous studies suggest that these cardiovascular changes are caused by stimulation of pulmonary stretch receptors (PSRs) during ventilation, it has been noted in other studies that blood flows often change prior to the initiation of breathing. Given the uncertainty regarding the role of PSRs in the regulation of central vascular blood flows, we examined the effect of manipulating lung volume (and therefore PSR stimulation) on blood flows and heart rate in the freshwater turtle Trachemys scripta. Turtles were instrumented with blood flow probes on the left aortic arch and the left pulmonary artery for measurements of blood flow, and catheters were inserted into both lungs for manipulation of lung volume. In both anaesthetized and fully recovered animals, reductions or increases in lung volume by withdrawal of lung gas or injection of air, N2, O2 or 10% CO2 (in room air) had no effect on blood flows. Furthermore, simulations of normal breathing bouts by withdrawal and injection of lung gas did not alter Qpul or fH. We conclude that stimulation of PSRs is not sufficient to elicit cardiovascular changes and that the large increase in Qpul and fH normally observed during spontaneous ventilation are probably caused by a simultaneous feedforward control of central origin.
The effects of artificial lung inflation on pulmonary blood flow and heart rate in the turtle Trachemys scripta.
J Herman, T Wang, A W Smits, J W Hicks; The effects of artificial lung inflation on pulmonary blood flow and heart rate in the turtle Trachemys scripta.. J Exp Biol 1 October 1997; 200 (19): 2539–2545. doi: https://doi.org/10.1242/jeb.200.19.2539
Download citation file:
Advertisement
Cited by
In the field: an interview with Harald Wolf
(update)-Conversation.jpg?versionId=3772)
In our new Conversation, Harald Wolf talks about his fieldwork experiences working with desert ants in Tunisia to understand their navigation.
Propose a new Workshop
-GSWorkshop.png?versionId=3772)
Our Workshops bring together leading experts and early-career researchers from a range of scientific backgrounds. Applications are now open to propose Workshops for 2024, one of which will be held in a Global South country.
Julian Dow steps down and John Terblanche joins the JEB team
-NewEditor.png?versionId=3772)
After 15 years with the journal, Julian Dow from University of Glasgow, UK, is stepping down as a Monitoring Editor. We wish Julian all the best for the future and welcome John Terblanche, Stellenbosch University, South Africa, who is joining the team. Julian talks about his long association with The Company of Biologists and the journal and John tells us about his life and career in this News article.
An accelerometer-derived ballistocardiogram method for detecting heart rate in free-ranging marine mammals
-Whales.jpg?versionId=3772)
Max Czapanskiy and co show how the resting heart rates of blue whales are immortalized in the accelerometry traces collected by motion sensing data tags.
Global change and physiological challenges for Amazonian fish
-Review.png?versionId=3772)
In their Review, Adalberto Luis Val and Chris Wood discuss the physiological threats to the unique and diverse fish fauna of Amazonia.