RESPIRATORY EFFECTS OF DOPAMINE-INDUCED INHIBITION OF CHEMOSENSORY INFLOW
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Date
1980
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Abstract
In pentobarbitone anesthetized cats, intracarotid injections of dopamine (DA) 0.05-20 .mu.g produced transient ventilatory depression, enhanced by section of the contralateral carotid nerve and abolished by section of the ipsilateral one. I.v. injections of DA 0.02-2 .mu.g .cntdot. kg-1 also induced transient hypoventilation; this effect was abolished by bilateral section of the carotid nerves. Slow i.v. infusion of DA 10 .mu.g .cntdot. kg-1 .cntdot. min-1 elicited initially a pronounced hypoventilation followed by a steady-state of mild ventilatory depression; these changes were absent after bilateral carotid neurotomy. Recordings from carotid nerves showed that DA-induced decreases of chemosensory activity to 50% of its control did not modify ventilation; chemosensory arrests transiently depressed ventilation to 40-75% of its control level. Interactions between the ventilatory and chemosensory depressant effects of hyperoxia and DA administration were studied. Reflex decrease in ventilation caused by DA injections apparently provides a measure of the tonic chemosensory drive exerted upon the respiratory center.