Studies on the influence of monoamines on the cerebrovascular response to arterial hypoxia

The cerebrovascular response to arterial hypoxia was studied during blockade of the vascular dopamine receptors and during alpha-adrenergic receptor stimulation and blockade in anaesthetized dogs. Dopamine receptor blockade with pimozide or haloperidol invariably decreased the degree of hypoxic vasodilatation in the brain pointing to a functional role of dopamine in this situation. Alpha-receptor blockade did not change the response, while stimulation of these receptors decreased the dilatory response even in deep arterial hypoxia.