EFFECTS OF A CONTINUOUS INFUSION OF DOPAMINE ON THE VENTILATORY AND CAROTID BODY RESPONSES TO HYPOXIA IN CATS

Tohru Ide, Machiko Shirahata, Chung‐Long ‐L Chou, Robert S. Fitzgerald

Research output: Contribution to journalArticle

Abstract

1. We investigated how a continuous infusion of dopamine (DA; 5μg/kg per min), which is often used clinically, would affect the ventilation and carotid chemoreceptor neural activity in anaesthetized cats. 2. In anaesthetized, spontaneously breathing cats, tidal volume (Vt) and respiratory frequency (f) were continuously monitored at five levels of inspired oxygen (P102= 110,130, 150, 170, 760mmHg) during Da or saline infusion. Vt and f were sampled for 1 min after 3 min exposure to each level of P102. Time control study was also performed. 3. DA infusion significantly lowered VT under both normoxia and hypoxia in seven of eight cats. Respiratory frequency was not affected by DA infusion. Depression of ventilation during post‐hypoxic hyperoxia was augmented by DA infusion. Chemodenervntion abolished the ventilatory response to hypoxia and DA did not further affect the ventilatory response to hypoxia. 4. In a second group of artificially ventilated cats, carotid chemoreceptor neural activity was recorded at five levels of arterial oxygen tension. DA infusion significantly depressed carotid chemoreceptor neural activity during normoxia and hypoxia in six of seven cats. 5. These findings suggest that changes in ventilation during low dosage of DA infusion closely correlate with carotid body neural output. A predominant effect of this dosage of DA (5 μg/kg per min) was depression in the ventilatory response to hypoxia due to an inhibition of carotid body neural output.

Original languageEnglish (US)
Pages (from-to)658-664
Number of pages7
JournalClinical and Experimental Pharmacology and Physiology
Volume22
Issue number9
DOIs
StatePublished - Sep 1995

Keywords

  • carotid body
  • catecholamine
  • chemoreceptor
  • dopamine
  • hypoxia
  • hypoxic response
  • ventilation
  • ventilatory response.

ASJC Scopus subject areas

  • Physiology
  • Pharmacology
  • Physiology (medical)

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