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Organismal Responses to Hypoxemic Challenges

  • Robert S. FitzgeraldEmail author
  • Gholam A. Dehghani
  • Samara Kiihl
Chapter
Part of the Advances in Experimental Medicine and Biology book series (AEMB, volume 860)

Abstract

As a counterpoint to the volumes of beautiful work exploring how the carotid bodies (CBs) sense and transduce stimuli into neural traffic, this study explored one organismal reflex response to such stimulation. We challenged the anesthetized, paralyzed, artificially ventilated cat with two forms of acute hypoxemia: 10 % O2/balance N2 (hypoxic hypoxia [HH] and carbon monoxide hypoxia [COH]). HH stimulates both CBs and aortic bodies (ABs), whereas COH stimulates only the ABs. Our design was to stimulate both with HH (HHint), then to stimulate only the ABs with COH (COHint); then, after aortic depressor nerve transaction, only the CBs with HH (HHabr), and finally neither with COH (COHabr). We recorded whole animal responses from Group 1 cats (e.g., cardiac output, arterial blood pressure, pulmonary arterial pressure/and vascular resistance) before and after sectioning the aortic depressor nerves. From Group 2 cats (intact) and Group 3 cats (aortic body resected) we recorded the vascular resistance in several organs (e.g., brain, heart, spleen, stomach, pancreas, adrenal glands, eyes). The HHint challenge was the most effective at keeping perfusion pressures adequate to maintain homeostasis in the face of a systemic wide hypoxemia with locally mediated vasodilation. The spleen and pancreas, however, showed a vasoconstrictive response. The adrenals and eyes showed a CB-mediated vasodilation. The ABs appeared to have a significant impact on the pulmonary vasculature as well as the stomach. Chemoreceptors via the sympathetic nervous system play the major role in this organism’s response to hypoxemia.

Keywords

Hypoxemia Chemoreceptors Organ vascular resistances 

Notes

Acknowledgement

The authors gratefully acknowledge the support of the National Institutes of Health (NHLBI; HL 0-50712-13) for this study.

References

  1. Alvarez R, de Alvarez E (1988) Carotid sinus receptors participate in glucose homeostasis. Respir Physiol 72:347–360CrossRefGoogle Scholar
  2. deB Daly IB, deB Daly MB (1957) The effects of stimulation of the carotid body chemoreceptors on pulmonary vascular resistance in the dog. J Physiol Lond 137:436–446CrossRefPubMedCentralGoogle Scholar
  3. Fitzgerald RS, Traystman RJ (1980) Peripheral chemoreceptors and the cerebral vascular response to hypoxemia. Fed Proc 39:2674–2676PubMedGoogle Scholar
  4. Fitzgerald RS, Dehghani GA, Sham JSK, Shirahata M, Mitzner WA (1992) Peripheral chemoreceptor modulation of the pulmonary vasculature in the cat. J Appl Physiol 73:20–29PubMedGoogle Scholar
  5. Fitzgerald RS, Dehghani GA, Kiihl S (2013a) Autonomic control of the cardiovascular system in the cat during hypoxemia. Auton Neurosci Basic Clin 174:21–30CrossRefGoogle Scholar
  6. Fitzgerald RS, Dehghani GA, Kiihl S (2013b) Autonomic regulation of organ vascular resistances during hypoxemia. Auton Neurosci Basic Clin 177:181–193CrossRefGoogle Scholar
  7. Lahiri S, Mulligan E, Nishino T, Mokashi A, Davies RO (1981) Relative responses of aortic body and carotid body chemoreceptors to carboxyhemoglobinemia. J Appl Physiol 50:580–586PubMedGoogle Scholar
  8. Levitzky MG (1979) Chemoreceptor stimulation and hypoxic pulmonary vasoconstriction in conscious dogs. Respir Physiol 37:151–160PubMedCrossRefGoogle Scholar
  9. Levitzky MG, Newell JC, Krasney JA, Dutton RE (1977) Chemoreceptor influence on pulmonary blood flow during unilateral hypoxia in dogs. Respir Physiol 31:345–356PubMedCrossRefGoogle Scholar
  10. Little R, Oberg B (1975) Circulatory responses to stimulation of the carotid body chemoreceptors in the cat. Acta Physiol Scand 93:34–51PubMedCrossRefGoogle Scholar
  11. Marshall JM (1994) Peripheral chemoreceptors and cardiovascular regulation. Physiol Rev 74:543–594PubMedGoogle Scholar
  12. Marshall JM, Metcalfe JD (1989) Analysis of factors that contribute to cardiovascular changes induced in the cat by graded levels of systemic hypoxia. J Physiol 412:429–448PubMedCrossRefPubMedCentralGoogle Scholar
  13. Marshall JM, Metcalfe JD (1990) Effects of systemic hypoxia on the distribution of cardiac output in the rat. J Physiol 426:335–353PubMedCrossRefPubMedCentralGoogle Scholar
  14. Weissman ML, Rubinstein EH, Sonnenschein RR (1976) Vascular responses to short-term systemic hypoxia, hypercapnia, and asphyxia in the cat. Am J Physiol 230:595–601PubMedGoogle Scholar
  15. Wilson LB, Levitzky MG (1989) Chemoreflex blunting of hypoxic pulmonary vasoconstriction is vagally mediated. J Appl Physiol 66:782–791PubMedGoogle Scholar

Copyright information

© Springer International Publishing Switzerland 2015

Authors and Affiliations

  • Robert S. Fitzgerald
    • 1
    • 2
    • 3
    Email author
  • Gholam A. Dehghani
    • 1
  • Samara Kiihl
    • 4
  1. 1.Departments of Environmental Health SciencesThe Johns Hopkins University Medical InstitutionsBaltimoreUSA
  2. 2.Departments of PhysiologyThe Johns Hopkins University Medical InstitutionsBaltimoreUSA
  3. 3.Departments of MedicineThe Johns Hopkins University Medical InstitutionsBaltimoreUSA
  4. 4.Departments of BiostatisticsThe Johns Hopkins University Medical InstitutionsBaltimoreUSA

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