Influence of the Carotid Baroreflex on Cerebral Blood Flow During Seated Upright Rest

Eubank, Wendy L., Influence of Carotid Baroreflex on Cerebral Blood Flow During Seated Upright Rest. Master of Science (Integrative Physiology), July, 2007, 25 pp., 1 table, 4 illustrations, 34 references. This study tested the hypothesis that sympathetic activation via the carotid baroreflex directly influences cerebral vasomotion during seated upright test. This study also examined the effects of pulsatile neck pressure (NP) and neck suction (NS) during seated upright rest in healthy human subjects. Changes in mean arterial pressure (MAP) and mean middle cerebral arterial velocity (MCA V mean), were measured. The power spectral density (PSD) of MAP of 0.1Hz increased during pulsatile NP and NS. The PSD of MCA V mean at 0.1Hz was much greater during NP than that of NS. There were no significant differences between end-tidal CO2 between each condition. These findings suggest that cerebral vasoconstriction during NP was a result of the autoregulatory response to the NP mediated pulsatile changes in arterial pressure and the NP induced sympathetically mediated vasoconstriction.