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 language | English (US) |
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Pages (from-to) | 658-664 |
Number of pages | 7 |
Journal | Clinical and Experimental Pharmacology and Physiology |
Volume | 22 |
Issue number | 9 |
DOIs | |
State | Published - Sep 1995 |
Externally published | Yes |
Keywords
- carotid body
- catecholamine
- chemoreceptor
- dopamine
- hypoxia
- hypoxic response
- ventilation
- ventilatory response.
ASJC Scopus subject areas
- Physiology
- Pharmacology
- Physiology (medical)