Role of sympathetic nervous system in activity-induced cerebral perfusion.
Several studies have suggested that autonomic neural control plays a role in regulation of cerebral blood flow (CBF), although the exact role of the sympathetic nervous system on CBF remains debated. The effects of sympathetic innervation on activity-induced cerebral perfusion changes in humans have not been studied. The aims of this study were therefore (a) to investigate patients with an "intrinsic" sympathetic deficit after stroke and healthy controls with regard to activity-induced cerebral perfusion changes, and (b) to investigate possible differences in functional CBF regulation between the anterior and posterior circulation. Cerebral blood flow velocity in the medial cerebral artery (MCA) and posterior cerebral artery (PCA) was investigated in 21 healthy controls and 17 patients with Wallenberg's syndrome using transcranial Doppler sonography during cortical activation of MCA and PCA territories, respectively. Patients with a central sympathetic deficit had a prolonged decrease of resistance in the MCA and showed a slower and less pronounced decrease of resistance in the PCA upon cortical activation. No difference was observed between the side with and without sympathetic deficit. Results suggest that (a) sympathetic efferents are involved in economisation of activity-induced changes of cerebral perfusion in the anterior circulation, (b) activity-induced sympathetic regulation of blood flow differs between the anterior and posterior vascular territories in humans and (c) a possible resting sympathetic tonus on extraparenchymal vessel might exist in the posterior circulation.
Gierthmühlen
Janne
J
Division of Neurological Pain Research and Therapy, Department of Neurology, University Hospital of Schleswig-Holstein, Campus Kiel, Arnold-Heller-Strasse 3, Haus 41, Kiel, Germany. j.gierthmuehlen@neurologie.uni-kiel.de
Allardt
Arne
A
Sawade
Michael
M
Wasner
Gunnar
G
Baron
Ralf
R
D000328:Adult; D001921:Brain / Q000098:blood supply* / Q000502:physiology*; D002536:Cerebral Arteries / Q000000981:diagnostic imaging / Q000502:physiology*; D002560:Cerebrovascular Circulation / Q000502:physiology*; D005260:Female; D006801:Humans; D014854:Lateral Medullary Syndrome / Q000000981:diagnostic imaging / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D013564:Sympathetic Nervous System / Q000000981:diagnostic imaging / Q000502:physiology*; D017585:Ultrasonography, Doppler, Transcranial