Abstract
Angiotensin II inhibits baroreceptor-evoked activity in cardiac vagal motoneurones. Because angiotensin III [( des-1-Asp ]angiotensin II) is a less potent pressor agent than angiotensin II, and has been reported not to share some of the actions of angiotensin II within the central nervous system, its influence on central vagal pathways was examined here. In unanaesthetized sheep equipressor doses of angiotensins II and III similarly inhibited the baroreceptor-cardioinhibitory reflex, a reflex which is almost wholly dependent on cardiac vagal activity. In anaesthetized dogs, equipressor doses of angiotensin II and III were equally effective in inhibiting the cardiac vagal activity usually evoked by rises in arterial pressure. This was established by direct recordings of activity in single cardiac vagal efferent nerve fibres. Direct recordings from single baroreceptor nerves in anaesthetized dogs showed that the angiotensins do not depress the receptor responses to elevations in blood pressure. It is concluded that equipressor doses of angiotensin III and angiotensin II inhibit central vagal pathways to the same extent.
Full text
PDFSelected References
These references are in PubMed. This may not be the complete list of references from this article.
- Aiken J. W., Reit E. Stimulation of the cat stellate ganglion by angiotensin. J Pharmacol Exp Ther. 1968 Jan;159(1):107–114. [PubMed] [Google Scholar]
- Blair-West J. R., Coghlan J. P., Denton D. A., Funder J. W., Scoggins B. A., Wright R. D. The effect of the heptapeptide (2-8) and hexapeptide (3-8) fragments of angiotensin II on aldosterone secretion. J Clin Endocrinol Metab. 1971 Apr;32(4):575–578. doi: 10.1210/jcem-32-4-575. [DOI] [PubMed] [Google Scholar]
- Blumberg A. L., Ackerly J. A., Peach M. J. Differentiation of neurogenic and myocardial angiotensin II receptors in isolated rabbit atria. Circ Res. 1975 Jun;36(6):719–726. doi: 10.1161/01.res.36.6.719. [DOI] [PubMed] [Google Scholar]
- Farr W. C., Grupp G. Sympathetically mediated effects of angiotensin on the dog heart in situ. J Pharmacol Exp Ther. 1967 Jun;156(3):528–537. [PubMed] [Google Scholar]
- Fitzsimons J. T., Kucharczyk J., Richards G. Systemic angiotensin-induced drinking in the dog: a physiological phenomenon. J Physiol. 1978 Mar;276:435–448. doi: 10.1113/jphysiol.1978.sp012245. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Fitzsimons J. T., Setler P. E. The relative importance of central nervous catecholaminergic and cholinergic mechanisms in drinking in response to antiotensin and other thirst stimuli. J Physiol. 1975 Sep;250(3):613–631. doi: 10.1113/jphysiol.1975.sp011073. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Freeman R. H., Davis J. O., Lohmeier T. E. Des-1-Asp-angiotensin II. Possible intrarenal role in homeostasis in the dog. Circ Res. 1975 Jul;37(1):30–34. doi: 10.1161/01.res.37.1.30. [DOI] [PubMed] [Google Scholar]
- Goodfriend T. L., Peach M. J. Angiotensin III: (DES-Aspartic Acid-1)-Angiotensin II. Evidence and speculation for its role as an important agonist in the renin - angiotensin system. Circ Res. 1975 Jun;36(6 Suppl 1):38–48. doi: 10.1161/01.res.36.6.38. [DOI] [PubMed] [Google Scholar]
- Hughes J., Roth R. H. Evidence that angiotensin enhances transmitter release during sympathetic nerve stimulation. Br J Pharmacol. 1971 Feb;41(2):239–255. doi: 10.1111/j.1476-5381.1971.tb08025.x. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 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]
- Lewis G. P., Reit E. The action of angiotensin and bradykinin on the superior cervical ganglion of the cat. J Physiol. 1965 Aug;179(3):538–553. doi: 10.1113/jphysiol.1965.sp007679. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 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]
- 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]
- Ramsay D. J., Reid I. A. Some central mechanisms of thirst in the dog. J Physiol. 1975 Dec;253(2):517–525. doi: 10.1113/jphysiol.1975.sp011204. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Scroop G. C., Lowe R. D. Efferent pathways of the cardiovascular response to vertebral artery infusions of angiotensin in the dog. Clin Sci. 1969 Dec;37(3):605–619. [PubMed] [Google Scholar]
- 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]