In 1954 an interesting paper by Meyer, Fang, and Denny-Brown1 presented evidence that makes possible a new interpretation of some puzzling features in the response of cerebral arteries to autonomic stimulation.
For the past 20 years there has been general acceptance of the thesis that arteries of the mammalian brain are regulated to a minor extent by vasomotor nerves.2 The evidence in favor of this is strong. There remain unexplained, however, atypical findings, such as the following: Section of the sympathetic trunk in the neck causes prompt dilatation of cutaneous branches of the external carotid artery, but no dilatation of the pial arteries; sympathetic nerve degeneration (following excision of cervical ganglia) causes increased epinephrine sensitivity of the pupil but not of the pial arteries.
The purpose of the present article is threefold: (1) to illustrate ways in which pial arteries differ from extracranial arteries; (2) to consider a
FORBES HS. Regulation of the Cerebral Vessels—New Aspects. AMA Arch NeurPsych. 1958;80(6):689-695. doi:10.1001/archneurpsyc.1958.02340120025004