 Some dopamine receptors are located in the walls of arteries, where they act as a vasodilator and an inhibitor of norepinephrine release.These responses might be activated by dopamine released from the carotid body under conditions of low oxygen, but whether arterial dopamine receptors perform other biologically useful functions is not known.Beyond its role in modulating blood flow, there are several peripheral systems in which dopamine circulates within a limited area and performs an exocrine or paracrine function.