Circulatory galanin levels increase severalfold with intense orthostatic challenge in healthy humans

• Published in: Journal of applied physiology (1985) 2006-03, Vol.100 (3), p.844-849
• Main Authors: Hinghofer-Szalkay, Helmut G, Rossler, Andreas, Evans, Joyce M, Stenger, Michael B, Moore, Fritz B, Knapp, Charles F
• Format: Article
• Language: English
• Subjects: Adult; Arginine Vasopressin - blood; Biological and medical sciences; Cardiovascular Physiological Phenomena; Cardiovascular system; Dizziness - blood; Female; Fundamental and applied biological sciences. Psychology; Galanin - blood; Gravity, Altered; Health; Hemodynamics; Humans; Lower Body Negative Pressure; Male; Plasma; Posture; Radioimmunoassay; Stress, Physiological - blood; Tilt-Table Test
• ISSN: 8750-7587; 1522-1601
• DOI: 10.1152/japplphysiol.01039.2005

1 Institute for Adaptive and Spaceflight Physiology, Wormgasse 9, and 2 Institute of Physiology, Center for Physiological Medicine, Medical University, Graz, Austria; 3 The Center for Biomedical Engineering, University of Kentucky, Lexington Kentucky; and 4 National Aeronautics and Space Administration Ames Center for Biological and Gravitational Research, Moffett Field, California Submitted 25 August 2005 ; accepted in final form 23 November 2005 The purpose of this study was to test the hypothesis that plasma galanin concentration (pGal) is regularly increased in healthy humans with extensive orthostatic stress. Twenty-six test persons (14 men, 12 women) were brought to an orthostatic end point via a progressive cardiovascular stress (PCS) protocol consisting of 70° head-up tilt plus increasing levels of lower body negative pressure until either hemodynamically defined presyncope or other signs of orthostatic intolerance occurred (nausea, clammy skin, excessive sweating, pallor of the skin). We further tested for possible gender, gravitational, and muscular training influences on plasma pGal responses: PCS was applied before and after 3 wk of daily vertical acceleration exposure training on a Human Powered Centrifuge. Test persons were randomly assigned to active (with bicycle work) or passive (without work) groups (seven men, six women in each group). Resting pGal was 26 ± 3 pg/ml in men and 39 ± 15 pg/ml in women (not significant); women had higher galanin responses (4.9-fold increase) than men (3.5-fold, P = 0.017) to PCS exposure. Overall, PCS increased pGal to 186 ± 5 pg/ml ( P = 0.0003), without significant differences between presyncope vs. orthostatic intolerance, pre- vs. postcentrifuge, or active vs. passive gravitational training. Increases in pGal were poorly related to synchronous elevations in plasma vasopressin. We conclude that galanin is regularly increased in healthy humans under conditions of presyncopal orthostatic stress, the response being independent of gravity training but larger in women than in men. blood pressure stability; syncope; hormones; gender differences Address for reprint requests and other correspondence: H. G. Hinghofer-Szalkay, Institute of Physiology, Medical Univ., Harrachgasse 21, A-8010 Graz, Austria (e-mail: helmut.hinghofer{at}meduni-graz.at )