EFFECTS OF DOPAMINE ON THE CEREBRAL BLOOD FLOW IN THE DOG

Abstract

The effect of dopamine on the cerebral blood flow was studied in anaesthetized dogs. Cerebral blood flow was measured by the radio-active gas elimination technique with external γ-registration. Dopamine was administered by continuous infusion. Dopamine was found to influence the cerebral blood flow in two different ways: first by exerting an α-adrenergic receptor stimulating effect, resulting in a blood flow decrease. This was found in response to very small doses of dopamine and then once again with larger doses. Secondly, dopamine was found to stimulate specific dopamine receptors in the cerebral vessels, resulting in vasodilatation, sometimes with a pronounced flow increase. This occurred mainly in response to medium doses of dopamine. Autoregulation functioned well both during stimulation and blockade of these receptors.