Abstract
1. The circulatory effects of artificial hyperventilation with air and low oxygen mixtures were studied in rabbits anaesthetized with chloralose-urethane and given decamethonium iodide. The role of vagal afferents in the response to hypoxia was also assessed in spontaneously breathing unanaesthetized and anaesthetized animals.
2. In the anaesthetized rabbit artificial hyperventilation inhibited all the changes in autonomic activity to the heart and peripheral circulation resulting from stimulation of the arterial chemoreceptors, and also reduced vagal efferent tone. In animals with section of the carotid sinus and aortic nerves the changes in autonomic activity observed during hypoxia and hyperventilation were much smaller than in normal animals and affected only cardiac autonomic activity.
3. The effects of hyperventilation during hypoxia were mediated chiefly through vagal afferents rather than through the effects of hypocapnia. In the absence of changes in autonomic activity (e.g. during artificial hyperventilation with air) the circulatory effects were small and less clearly related to afferent vagal activity.
4. In the spontaneously breathing anaesthetized and unanaesthetized rabbit vagal afferent activity resulting from the respiratory response to hypoxia inhibits sympatho-adrenal activity in the same way as during hypoxia with artificial hyperventilation.
5. The importance of the vagal afferent input in the rabbit is discussed in relation to the qualitative differences in circulatory response with increasing severity of hypoxia, and in relation to the effects of anaesthesia.
Full text
PDFSelected References
These references are in PubMed. This may not be the complete list of references from this article.
- Chalmers J. P., Isbister J. P., Korner P. I., Mok H. Y. The role of the sympathetic nervous system in the circulatory response of the rabbit to arterial hypoxia. J Physiol. 1965 Nov;181(1):175–191. doi: 10.1113/jphysiol.1965.sp007753. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Chalmers J. P., Korner P. I., White S. W. Local and reflex factors affecting the distribution of the peripheral blood flow during arterial hypoxia in the rabbit. J Physiol. 1967 Sep;192(2):537–548. doi: 10.1113/jphysiol.1967.sp008315. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Chalmers J. P., Korner P. I., White S. W. The relative roles of the aortic and carotid sinus nerves in the rabbit in the control of respiration and circulation during arterial hypoxia and hypercapnia. J Physiol. 1967 Feb;188(3):435–450. doi: 10.1113/jphysiol.1967.sp008148. [DOI] [PMC free article] [PubMed] [Google Scholar]
- DALY M. D., HAZZLEDINE J. L. THE EFFECTS OF ARTIFICIALLY INDUCED HYPERVENTILATION ON THE PRIMARY CARDIAC REFLEX RESPONSE TO STIMULATION OF THE CAROTID BODIES IN THE DOG. J Physiol. 1963 Oct;168:872–889. doi: 10.1113/jphysiol.1963.sp007228. [DOI] [PMC free article] [PubMed] [Google Scholar]
- DALY M. D., SCOTT M. J. The cardiovascular responses to stimulation of the carotid body chemoreceptors in the dog. J Physiol. 1963 Jan;165:179–197. doi: 10.1113/jphysiol.1963.sp007051. [DOI] [PMC free article] [PubMed] [Google Scholar]
- DE DALY M. B., SCOTT M. J. The effects of stimulation of the carotid body chemoreceptors on heart rate in the dog. J Physiol. 1958 Nov 10;144(1):148–166. doi: 10.1113/jphysiol.1958.sp006092. [DOI] [PMC free article] [PubMed] [Google Scholar]
- DOWNING S. E., REMENSNYDER J. P., MITCHELL J. H. Cardiovascular responses to hypoxic stimulation of the carotid bodies. Circ Res. 1962 Apr;10:676–685. doi: 10.1161/01.res.10.4.676. [DOI] [PubMed] [Google Scholar]
- Daly M. D., Robinson B. H. An analysis of the reflex systemic vasodilator response elicited by lung inflation in the dog. J Physiol. 1968 Mar;195(2):387–406. doi: 10.1113/jphysiol.1968.sp008464. [DOI] [PMC free article] [PubMed] [Google Scholar]
- De Burgh Daly M., Hazzledine J. L., Ungar A. The reflex effects of alterations in lung volume on systemic vascular resistance in the dog. J Physiol. 1967 Feb;188(3):331–351. doi: 10.1113/jphysiol.1967.sp008142. [DOI] [PMC free article] [PubMed] [Google Scholar]
- DeGeest H., Levy M. N., Zieske H. Reflex effects of cephalic hypoxia, hypercapnia, and ischemia upon ventricular contractility. Circ Res. 1965 Oct;17(4):349–358. doi: 10.1161/01.res.17.4.349. [DOI] [PubMed] [Google Scholar]
- KONTOS H. A., MAUCK H. P., Jr, RICHARDSON D. W., PATTERSON J. L., Jr MECHANISM OF CIRCULATORY RESPONSES TO SYSTEMIC HYPOXIA IN THE ANESTHETIZED DOG. Am J Physiol. 1965 Aug;209:397–403. doi: 10.1152/ajplegacy.1965.209.2.397. [DOI] [PubMed] [Google Scholar]
- KORNER P. I. Circulatory adaptations in hypoxia. Physiol Rev. 1959 Oct;39:687–730. doi: 10.1152/physrev.1959.39.4.687. [DOI] [PubMed] [Google Scholar]
- KORNER P. I., EDWARDS A. W. The immediate effects of acute hypoxia on the heart rate, arterial pressure, cardiac output and ventilation of the unanaesthetized rabbit. Q J Exp Physiol Cogn Med Sci. 1960 Apr;45:113–122. doi: 10.1113/expphysiol.1960.sp001449. [DOI] [PubMed] [Google Scholar]
- Korner P. I., Langsford G., Starr D., Uther J. B., Ward W., White S. W. The effects of chloralose-urethane and sodium pentobarbitone anaesthesia on the local and autonomic components of the circulatory response to arterial hypoxia. J Physiol. 1968 Dec;199(2):283–302. doi: 10.1113/jphysiol.1968.sp008654. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Korner P. I. The effect of section of the carotid sinus and aortic nerves on the cardiac output of the rabbit. J Physiol. 1965 Sep;180(2):266–278. doi: 10.1113/jphysiol.1965.sp007702. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Korner P. I. The role of the arterial chemoreceptors and baroreceptors in the circulatory response to hypoxia of the rabbit. J Physiol. 1965 Sep;180(2):279–303. doi: 10.1113/jphysiol.1965.sp007703. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Korner P. I., Uther J. B., White S. W. Circulatory effects of chloralose-urethane and sodium pentobarbitone anaesthesis in the rabbit. J Physiol. 1968 Dec;199(2):253–265. doi: 10.1113/jphysiol.1968.sp008652. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Scott M. J. The effects of hyperventilation on the reflex cardiac response from the carotid bodies in the cat. J Physiol. 1966 Oct;186(2):307–320. doi: 10.1113/jphysiol.1966.sp008036. [DOI] [PMC free article] [PubMed] [Google Scholar]
- White S. W., Chalmers J. P., Hilder R., Korner P. I. Local thermodilution method for measuring blood flow in the portal and renal veins of the unanaesthetized rabbit. Aust J Exp Biol Med Sci. 1967 Oct;45(5):453–468. doi: 10.1038/icb.1967.45. [DOI] [PubMed] [Google Scholar]