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| Research article summary (published 29 Jun 2003): |
Relationship between blood pressure, sleep K-complexes, and muscle sympathetic nerve activity in humans.
Full Abstract
Stage 2 sleep is characterized by the EEG appearance of "K-complexes" and blood pressure oscillations. K-complexes may be directly related to blood pressure changes or they may reflect central sympathetic activation. We analyzed the temporal relationship among K-complexes, heart rate (HR), blood pressure (BP), and muscle sympathetic nerve activity (MSNA) during sleep in eight healthy volunteers (3 men and 5 women, age 22-41 yr). Most K-complexes presented as single large complexes (56 +/- 20%), followed by single small complexes (15 +/- 14%) and as couplets or triplets (13 +/- 6%). Single large K-complexes were preceded by a baroreflex-mediated increase of MSNA in approximately one-half (55%) of the cases. Detailed analysis of HR, BP, and MSNA was possible in 63 (45%) large single K-complexes not disturbed by preceding baroreflex-related changes. Systolic and diastolic BP and MSNA increased significantly after single events (22.5 +/- 13, 5.2 +/- 2.1, and 6.5 +/- 3.0%). Mean sympathetic baroreflex latency was similar after the single large K-complexes compared with the mean value during stage 2 sleep (1,290 +/- 126 vs. 1,279 +/- 61 ms). The area under the burst was significantly increased after single large K-complexes (median 3.9 vs. 9.0 arbitrary units, P < 0.03). The results support the hypothesis that K-complexes express cortical activation leading to temporary facilitation of sympathetic outflow in a graded fashion. Their functional effects appear to be independent of baroreflex modulation of MSNA in approximately 50% of the cases.
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Author information
Author/s: Tank, Jens (J); Diedrich, Andre (A); Hale, Nanette (N); Niaz, Faiz E (FE); Furlan, Raffaello (R); Robertson, Rose Marie (RM); Mosqueda-Garcia, Rogelio (R);
Affiliation: Helios Klinikum Berlin, Clinical Research Center, Franz Volhard Clinic, Charité Campus-Buch, Humboldt Univ. Berlin, Wiltberg Str. 50, 13125 Berlin, Germany. tank(-atsign-)fvk-berlin.de
Journal and publication information
Publication Type: Journal Article
Journal: American journal of physiology. Regulatory, integrative and comparative physiology (Am J Physiol Regul Integr Comp Physiol), published in United States. (Language: eng)
Reference: 2003-Jul; vol 285 (issue 1) : pp R208-14
Dates: Created 2003/06/09; Completed 2003/07/24; Revised 2004/11/17;
PMID: 12793998, status: MEDLINE (last retrieval date: 11/6/2008)
Sourced from the National Library of Medicine. Abstract text and other information may be subject to copyright.
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