Skip to main content
The Journal of Physiology logoLink to The Journal of Physiology
. 1985 Oct;367:1–11. doi: 10.1113/jphysiol.1985.sp015810

The effects and interactions of angiotensin and vasopressin on the heart of unanaesthetized sheep.

A C Caine, E R Lumbers, I A Reid
PMCID: PMC1193049  PMID: 4057096

Abstract

The effects of infusions of angiotensin and vasopressin, in stepwise concentrations, on the cardiac baroreflex and on cardiac output were studied in seven adult unanaesthetized sheep and compared with those obtained with infusions of phenylephrine. Six animals were treated with the beta-adrenoceptor blocking drug, propranolol (in order to inhibit the effects of the sympathetic nervous system on the heart). One animal was not treated with propranolol. In those animals in which arterial pressure increased during infusion of vasopressin, the slope of the systolic pressure-pulse interval relation was greater than that seen when phenylephrine was used to increase arterial pressure. Compared with the cardiac response to pressor doses of phenylephrine, infusions of angiotensin were associated with a lesser degree of cardiac slowing and a lesser reduction in cardiac output. The effects of combined infusions of angiotensin and vasopressin on the cardiac baroreflex were studied. In five sheep which were infused with a pressor dose of angiotensin (1.1 microgram/min), the stimulatory effect of vasopressin (1.0 u./min) on pulse interval and its depressant effect on cardiac output were attenuated. In seven sheep infused with 0.5 u./min of vasopressin, I.V. infusion of angiotensin (0.2-5.0 micrograms), produced a progressive decrease in pulse interval and increase in cardiac output as the dose was increased. Therefore, angiotensin can offset the cardioinhibitory effects of vasopressin. Since cardiac sympathetic activity was blocked and neither drug has any direct chronotropic effect on the heart, it would appear that these interactions between the two drugs affect the cardiac vagus either at a peripheral or central level.

Full text

PDF
3

Selected References

These references are in PubMed. This may not be the complete list of references from this article.

  1. Courtice G. P., Kwong T. E., Lumbers E. R., Potter E. K. Excitation of the cardiac vagus by vasopressin in mammals. J Physiol. 1984 Sep;354:547–556. doi: 10.1113/jphysiol.1984.sp015392. [DOI] [PMC free article] [PubMed] [Google Scholar]
  2. Hall R. C., Hodge R. L. Changes in catecholamine and angiotensin levels in the cat and dog during hemorrhage. Am J Physiol. 1971 Nov;221(5):1305–1309. doi: 10.1152/ajplegacy.1971.221.5.1305. [DOI] [PubMed] [Google Scholar]
  3. Heyndrickx G. R., Boettcher D. H., Vatner S. F. Effects of angiotensin, vasopressin, and methoxamine on cardiac function and blood flow distribution in conscious dogs. Am J Physiol. 1976 Nov;231(5 Pt 1):1579–1587. doi: 10.1152/ajplegacy.1976.231.5.1579. [DOI] [PubMed] [Google Scholar]
  4. Ismay M. J., Lumbers E. R., Stevens A. D. The action of angiotensin II on the baroreflex response of the conscious ewe and the conscious fetus. J Physiol. 1979 Mar;288:467–479. [PMC free article] [PubMed] [Google Scholar]
  5. Lee W. B., Ismay M. J., Lumbers E. R. Mechanisms by which angiotensin II affects the heart rate of the conscious sheep. Circ Res. 1980 Aug;47(2):286–292. doi: 10.1161/01.res.47.2.286. [DOI] [PubMed] [Google Scholar]
  6. Lumbers E. R., McCloskey D. I., Potter E. K. Inhibition by angiotensin II of baroreceptor-evoked activity in cardiac vagal efferent nerves in the dog. J Physiol. 1979 Sep;294:69–80. doi: 10.1113/jphysiol.1979.sp012915. [DOI] [PMC free article] [PubMed] [Google Scholar]
  7. Lumbers E. R., Potter E. K. Inhibition of the vagal component of the baroreceptor-cardioinhibitory reflex by angiotensin III in dogs and sheep. J Physiol. 1983 Mar;336:83–89. doi: 10.1113/jphysiol.1983.sp014568. [DOI] [PMC free article] [PubMed] [Google Scholar]
  8. Lumbers E. R., Reid I. A. The cardiovascular effects of intravertebral angiotensin II before and after treatment with clonidine. Clin Exp Pharmacol Physiol. 1981 Sep-Oct;8(5):531–535. doi: 10.1111/j.1440-1681.1981.tb00762.x. [DOI] [PubMed] [Google Scholar]
  9. Montani J. P., Liard J. F., Schoun J., Möhring J. Hemodynamic effects of exogenous and endogenous vasopressin at low plasma concentrations in conscious dogs. Circ Res. 1980 Sep;47(3):346–355. doi: 10.1161/01.res.47.3.346. [DOI] [PubMed] [Google Scholar]
  10. Parker P., Celler B. G., Potter E. K., McCloskey D. I. Vagal stimulation and cardiac slowing. J Auton Nerv Syst. 1984 Sep;11(2):226–231. doi: 10.1016/0165-1838(84)90080-8. [DOI] [PubMed] [Google Scholar]
  11. Potter E. K. Angiotensin inhibits action of vagus nerve at the heart. Br J Pharmacol. 1982 Jan;75(1):9–11. doi: 10.1111/j.1476-5381.1982.tb08752.x. [DOI] [PMC free article] [PubMed] [Google Scholar]
  12. Schwartz J., Reid I. A. Effect of vasopressin blockade on blood pressure regulation during hemorrhage in conscious dogs. Endocrinology. 1981 Nov;109(5):1778–1780. doi: 10.1210/endo-109-5-1778. [DOI] [PubMed] [Google Scholar]
  13. Severs W. B., Daniels-Severs A. E. Effects of angiotensin on the central nervous system. Pharmacol Rev. 1973 Sep;25(3):415–449. [PubMed] [Google Scholar]
  14. Smyth H. S., Sleight P., Pickering G. W. Reflex regulation of arterial pressure during sleep in man. A quantitative method of assessing baroreflex sensitivity. Circ Res. 1969 Jan;24(1):109–121. doi: 10.1161/01.res.24.1.109. [DOI] [PubMed] [Google Scholar]
  15. Szczepańska-Sadowska E. Hemodynamic effects of a moderate increase of the plasma vasopressin level in conscious dogs. Pflugers Arch. 1973;338(4):313–322. doi: 10.1007/BF00586073. [DOI] [PubMed] [Google Scholar]
  16. VARMA S., JOHNSEN S. D., SHERMAN D. E., YOUMANS W. B. Mechanisms of inhibition of heart rate by phenylephrine. Circ Res. 1960 Nov;8:1182–1186. doi: 10.1161/01.res.8.6.1182. [DOI] [PubMed] [Google Scholar]

Articles from The Journal of Physiology are provided here courtesy of The Physiological Society

RESOURCES