Autonomic Influences on Cardiac Function in the Newborn Lamb
- 1 November 1966
- journal article
- research article
- Published by Wolters Kluwer Health in Circulation Research
- Vol. 19 (5), 947-959
- https://doi.org/10.1161/01.res.19.5.947
Abstract
The influences of reflexly induced changes of sympathetic outflow to the heart on left ventricle contractility, heart rate, and systemic vascular resistance were studied in 26 technically successful experiments with newborn lambs ranging in age from 1 to 11 days. Reduction of brachiocephalic artery perfusion pressure was associated with a large increase of heart rate and of systemic vascular resistance. Under conditions of constant aortic pressure, heart rate and cardiac output, cephalic hypotension in most preparations induced a rapid onset of a fall of left ventricular end-diastolic pressure and an increase in the maximal rate of rise of left ventricular pressure (dp/dt max). Ventricular function curves obtained under conditions of constant aortic pressure and heart rate were shifted to the left. The average increase of stroke volume at left ventricular end-diastolic pressure of 10 cm H2O (SV10) was 23.3%, and of dp/dt max was 30.7% in the reactive preparations. The average of the largest responses for each preparation was an increase of SV10 of 42%, and for left ventricular dp/dt max, 48.8%. Three preparations previously subjected to carotid sinus nerve sectioning showed similar responses. No evidence for diminution of the response following parasympathetic blockade with atropine was found. In all preparations, ganglionic blockade virtually or completely eliminated the response.Keywords
This publication has 19 references indexed in Scilit:
- Aortic baroreceptor threshold and sensitivity in rabbits at different agesThe Journal of Physiology, 1964
- Negative Inotropic Effect of the Vagus Nerves upon the Canine VentricleScience, 1964
- RNA Concentrations in the Ventricles of Full-Term and Premature Rabbits Following BirthNature, 1964
- THE EFFECT OF BLOOD PRESSURE UPON CHEMORECEPTOR DISCHARGE TO HYPOXIA, AND THE MODIFICATION OF THIS EFFECT BY THE SYMPATHETIC‐ADRENAL SYSTEMQuarterly Journal of Experimental Physiology and Cognate Medical Sciences, 1964
- THE EFFECTS OF ACUTE HYPOXIA ON THE SYSTEMIC VENOUS AND ARTERIAL SYSTEMS AND ON MYOCARDIAL CONTRACTILE FORCEJCI Insight, 1962
- Cardiovascular Responses to Hypoxic Stimulation of the Carotid BodiesCirculation Research, 1962
- Baroreceptor reflexes in new‐born rabbitsThe Journal of Physiology, 1960
- Some cardiovascular responses in foetal, new‐born and adult rabbitsThe Journal of Physiology, 1957
- Chemoreceptor Impulses Activity Following Haemorrhage.Acta Physiologica Scandinavica, 1951
- Vagal reflexes appearing in asphyxia in rabbits at different agesThe Journal of Physiology, 1939