Potencies of doxapram and hypoxia in stimulating carotid-body chemoreceptors and ventilation in anesthetized cats

Anesthesiology. 1975 May;42(5):559-66. doi: 10.1097/00000542-197505000-00009.

Abstract

The effects of doxapram on carotid chemoreceptor activity and on ventilation (phrenic-nerve activity) were tested before and after denervation of the peripheral chemoreceptors in cats. Doxapram was found to be a potent stimulus to the carotid chemoreceptors; the stimulation produced by 1.0 mg/kg doxapram, iv, equalled that produced by a Pao2 of 38 torr. Doxapram also increased phrenic-nerve activity in doses as low as 0.2 mg/kg, iv. After denervation of the peripheral chemoreceptors, doxapram in doses as large as 6 mg/kg failed to stimulate ventilation. It is concluded that (in anesthetized cats) doxapram in doses of less than 6 mg/kg increases ventilation by direct stimulation of the carotid, and, probably, the aortic, chemoreceptors, not by a direct effect on the medullary respiratory center.

Publication types

  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Anesthesia*
  • Animals
  • Aorta / innervation
  • Blood Pressure / drug effects
  • Carbon Dioxide / blood
  • Carotid Body / drug effects*
  • Carotid Sinus / innervation
  • Cats
  • Chloralose / administration & dosage
  • Denervation
  • Doxapram / administration & dosage
  • Doxapram / pharmacology*
  • Heart Rate / drug effects
  • Hypoxia / physiopathology*
  • Injections, Intraperitoneal
  • Injections, Intravenous
  • Neurons, Efferent / physiology
  • Oxygen / blood
  • Phrenic Nerve / physiology
  • Respiration / drug effects*
  • Tracheotomy
  • Urethane / administration & dosage

Substances

  • Carbon Dioxide
  • Chloralose
  • Urethane
  • Doxapram
  • Oxygen