Partial pharmacologic blockade shows sympathetic connection between blood pressure and cerebral blood flow velocity fluctuations

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

Journal

Book Volume: 365

Pages Range: 181-7

DOI: 10.1016/j.jns.2016.04.022

Abstract

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.

Authors with CRIS profile

Involved external institutions

Klinikum am Europakanal Erlangen Germany (DE) Paracelsus Medizinische Privatuniversität, Nürnberg Germany (DE) Klinik Neustadt an der Aisch Germany (DE)

How to cite

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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