Abstract
Altered baroreflex function may contribute to the cardiovascular changes associated with weightlessness. Since central blood volume (CBV) increases during simulated weightlessness we have examined the possibility that acute changes in CBV may modify baroreceptor function. We used graded head-up tilt (HUT) and head-down tilt (HDT) to induce changes in CBV, and neck suction to stimulate carotid baroreceptors, in 6 subjects. The increase in pulse interval induced by a negative pressure of 8.2 kPa (62 mm Hg) imposed for 10 s while supine was compared with the increase while tilted for 8 min at +/- 15 degrees, +/- 30 degrees and +/- 45 degrees. During HDT at 15 degrees the pulse interval over the first 5 cardiac cycles following suction onset was 51 +/- (SEM) 18 ms longer (p less than 0.05), at 30 degrees it was 61 +/- 20 ms longer (p less than 0.05), and at 45 degrees it was 74 +/- 35 ms longer (p less than 0.01), compared with supine. During HUT at 15 degrees the pulse interval was 25 +/- 9 ms shorter (p less than 0.05) than when supine, but was not significantly different at 30 degrees and 45 degrees. These responses occurred independently of changes in brachial blood pressure. Attenuation was also observed after 5 min (56 +/- 17...Continue Reading
References
Jan 1, 1976·Physiological Reviews·H R Kirchheim
Feb 1, 1979·Journal of Applied Physiology: Respiratory, Environmental and Exercise Physiology·Y A Mengesha, G H Bell
May 1, 1977·The Journal of Clinical Investigation·D L Eckberg, C R Orshan
Aug 1, 1977·The Journal of Physiology·D L Eckberg
Sep 1, 1977·Acta Physiologica Scandinavica·S BevegårdL E Lindblad
Sep 1, 1976·Journal of Applied Physiology·D L EckbergA L Mark
Jan 1, 1986·European Journal of Applied Physiology and Occupational Physiology·M H HarrisonJ E Greenleaf
Jan 1, 1972·Circulation Research·D L EckbergE Braunwald
Jan 1, 1974·Circulation Research·N Doba, D J Reis
Oct 1, 1971·Cardiovascular Research·T G PickeringP Sleight
Feb 1, 1966·The American Journal of Cardiology·P M Stevens
Sep 1, 1984·Journal of Applied Physiology: Respiratory, Environmental and Exercise Physiology·J E Greenleaf
Jan 1, 1983·Medicine and Science in Sports and Exercise·C G Blomqvist
Jun 1, 1982·Journal of Applied Physiology: Respiratory, Environmental and Exercise Physiology·G E BillmanH L Stone
Sep 1, 1979·Acta Astronautica·C S Leach
Apr 1, 1953·Physiological Reviews·T SJOSTRAND
Citations
Dec 1, 1996·Clinical Autonomic Research : Official Journal of the Clinical Autonomic Research Society·A LindqvistC Strömberg
Sep 1, 1990·Acta Astronautica·A GuellC Gharib
Jan 1, 1991·Acta Astronautica·V A Convertino
Jul 1, 1992·Acta Astronautica·A GuellC l Gharib
Aug 1, 1993·Acta Astronautica·R L HughsonC Gharib
Feb 1, 1995·Acta Astronautica·A Guell
Dec 1, 1987·Journal of the Autonomic Nervous System·F WeiseU Runge
Nov 1, 1995·Clinical Physiology·J HartikainenE Länsimies
Apr 8, 2003·The Journal of Physiology·P O O JuluR Hainsworth
Sep 10, 2016·Annals of Noninvasive Electrocardiology : the Official Journal of the International Society for Holter and Noninvasive Electrocardiology, Inc·Sten ÖstensonPyotr G Platonov
Feb 10, 2004·Journal of Applied Physiology·Tomi LaitinenJuha Hartikainen
Oct 12, 1999·Clinical Physiology·D D O'LearyR L Hughson
Jun 1, 1995·Hypertension·G C ButlerJ S Floras
Sep 19, 2007·The Journal of Physiological Sciences : JPS·Zhansheng ZhaoYasutaka Kurata
Aug 1, 1988·Acta Anaesthesiologica Scandinavica·L G EkmanB A Sjöqvist
May 1, 1994·Clinical Physiology·R L HughsonC Gharib
Mar 14, 2019·Computational and Mathematical Methods in Medicine·Agnieszka KazimierskaMagdalena Kasprowicz
Nov 18, 2000·American Journal of Physiology. Regulatory, Integrative and Comparative Physiology·K I IwasakiB D Levine
Jun 16, 2001·Journal of Applied Physiology·C KeylL Bernardi
Nov 19, 2015·Frontiers in Physiology·Alberto PortaFerdinando Raimondi
Jan 20, 2018·American Journal of Physiology. Heart and Circulatory Physiology·André L TeixeiraLauro C Vianna