Hilz MJ, Wang R, Marthol H, Liu M, Tillmann A, Riss S, Hauck P, Hoesl KM, Wasmeier G, Stemper B, Köhrmann M (2016)
Publication Type: Journal article
Publication year: 2016
Book Volume: 365
Pages Range: 181-7
DOI: 10.1016/j.jns.2016.04.022
Cerebral autoregulation (CA) dampens transfer of blood pressure (BP)-fluctuations onto cerebral blood flow velocity (CBFV). Thus, CBFV-oscillations precede BP-oscillations. The phase angle (PA) between sympathetically mediated low-frequency (LF: 0.03-0.15Hz) BP- and CBFV-oscillations is a measure of CA quality. To evaluate whether PA depends on sympathetic modulation, we assessed PA-changes upon sympathetic stimulation with and without pharmacologic sympathetic blockade. In 10 healthy, young men, we monitored mean BP and CBFV before and during 120-second cold pressor stimulation (CPS) of one foot (0°C ice-water). We calculated mean values, standard deviations and sympathetic LF-powers of all signals, and PAs between LF-BP- and LF-CBFV-oscillations. We repeated measurements after ingestion of the adrenoceptor-blocker carvedilol (25mg). We compared parameters before and during CPS, without and after carvedilol (analysis of variance, post-hoc t-tests, significance: p<0.05). Without carvedilol, CPS increased BP, CBFV, BP-LF- and CBFV-LF-powers, and shortened PA. Carvedilol decreased resting BP, CBFV, BP-LF- and CBFV-LF-powers, while PAs remained unchanged. During CPS, BPs, CBFVs, BP-LF- and CBFV-LF-powers were lower, while PAs were longer with than without carvedilol. With carvedilol, CPS no longer shortened resting PA. Sympathetic activation shortens PA. Partial adrenoceptor blockade abolishes this PA-shortening. Thus, PA-measurements provide a subtle marker of sympathetic influences on CA and might refine CA evaluation.
APA:
Hilz, M.-J., Wang, R., Marthol, H., Liu, M., Tillmann, A., Riss, S.,... Köhrmann, M. (2016). Partial pharmacologic blockade shows sympathetic connection between blood pressure and cerebral blood flow velocity fluctuations. Journal of the Neurological Sciences, 365, 181-7. https://doi.org/10.1016/j.jns.2016.04.022
MLA:
Hilz, Max-Josef, et al. "Partial pharmacologic blockade shows sympathetic connection between blood pressure and cerebral blood flow velocity fluctuations." Journal of the Neurological Sciences 365 (2016): 181-7.
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