It was concluded that the autonomic nervous system plays an important role in the mechanism of autoregulation of CBF and that his mechanism is independent of the chemical control of the cerebral vessels. This was confirmed by direct observation of the pial vessels in cats, where separate sites of action in the vascular tree for autoregulation and chemical control were demonstrated; the autoregulatory reaction was located in pial arteries with a diameter larger than 50 μ, and the reaction to carbon dioxide in pial arteries of smaller diameter (Gotoh et al. 1975).
They concluded that the arteries operating in autoregulation were the larger ones with the dense innervation, while the smaller arteries with sparse innervation were involved in chemical control.
Coronna and Plum (1973) demonstrated the absence of CBF autoregulation in a patient with a Shy-Drager syndrome who had a postganglionic denervation.
Gotoh et al (1979) subsequently showed that autoregulation in patients with this syndrome was impaired irrespective of the localization of the damage to the cervical sympathetic nervous system (preganglionic, central, postganglionic) as judged by the eye instillation test.
Handbook of Clinical Neurology,