Interaction between graviception and carotid baroreflex function in humans during parabolic flight-induced microgravity

• Published in: Journal of applied physiology (1985) Vol. 125; no. 2; pp. 634 - 641
• Main Authors: Ogoh, Shigehiko, Marais, Michaël, Lericollais, Romain, Denise, Pierre, Raven, Peter B, Normand, Hervé
• Format: Journal Article
• Language: English
• Published: United States American Physiological Society 01-08-2018
• Subjects: Baroreceptors; Blood pressure; Blood volume; Cardiovascular system; Flight; Gravitational effects; Gravity; Heart rate; Human health and pathology; Life Sciences; Microgravity; Neck; Parabolic flight; Reflexes; Suction; Tissues and Organs; Variation; Vestibular system; Weightlessness; blood pressure; cardiovascular system; carotid sinus pressure; otolith system
• ISSN: 8750-7587; 1522-1601
• DOI: 10.1152/japplphysiol.00198.2018

The aim of the present study was to assess carotid baroreflex (CBR) during acute changes in otolithic activity in humans. To address this question, we designed a set of experiments to identify the modulatory effects of microgravity on CBR function at a tilt angle of -2{degree sign}, which was identified to minimize changes in central blood volume during parabolic flight. During parabolic flight at 0g and 1g, CBR function curves were modelled from the heart rate (HR) and mean arterial pressure (MAP) responses to rapid pulse trains of neck pressure (NP) and neck suction (NS) ranging from +40 to -80 Torr; CBR control of HR (carotid-HR) and MAP (carotid-MAP) baroreflex function curves, respectively. The maximal gain (G
) of both carotid-HR and carotid-MAP baroreflex function curves were augmented during microgravity compared to 1g (carotid-HR, -0.53 to -0.80 beats/min/mmHg, P<0.05; carotid-MAP, -0.24 to -0.30 mmHg/mmHg, P<0.05). These findings suggest that parabolic flight-induced acute change of otolithic activity may modify CBR function and identifies that the vestibular system contributes to blood pressure regulation under fluctuations in gravitational forces.