Modulation of plasma adrenomedullin by epinephrine infusion during head up tilt

• Published in: European journal of applied physiology 2011-03, Vol.111 (3), p.531-537
• Main Authors: Roessler, Andreas, Goswami, Nandu, Haditsch, Bernd, Hinghofer-Szalkay, Helmut
• Format: Article
• Language: English
• Subjects: Adrenomedullin - blood; Adrenomedullin - metabolism; Adult; Biological and medical sciences; Biomedical and Life Sciences; Biomedicine; Blood pressure; Blood Pressure - drug effects; Blood Pressure - physiology; Cross-Over Studies; Dizziness - physiopathology; Electrodes; Epinephrine - administration & dosage; Epinephrine - pharmacology; Fundamental and applied biological sciences. Psychology; Head - physiology; Heart - drug effects; Heart - physiology; Heart rate; Heart Rate - drug effects; Heart Rate - physiology; Hemodynamics; Hemodynamics - drug effects; Hemodynamics - physiology; Hormones - blood; Human Physiology; Humans; Infusion Pumps; Male; Medical research; Occupational Medicine/Industrial Medicine; Original Article; Physiology; Plasma; Posture - physiology; Rest - physiology; Sports Medicine; Vertebrates: body movement. Posture. Locomotion. Flight. Swimming. Physical exercise. Rest. Sports; Young Adult
• ISSN: 1439-6319; 1439-6327
• DOI: 10.1007/s00421-010-1668-3

We investigated whether head up tilt (HUT) with and without simultaneous epinephrine infusion modulate plasma adrenomedullin. We studied eight healthy male volunteers, using two 5 min 70° HUT trials: control (saline infusion) and intervention (epinephrine infusion, titrated to a dose which increased supine systolic pressure by 20% above resting values). Protocols were randomized and separated by 2 weeks. Cardiac function and systolic time intervals, recorded using a phonocardiograph microphone, included left ventricular ejection time (LVET), pre-ejection period (PEP), PEP/LVET and electromechanical systole (QS2). Compared to saline infusion, epinephrine increased supine adrenomedullin (3.2 ± 0.8 pmol/l, i.e., mean ± SEM, respectively), heart rate (HR) (+11.3 ± 2.6 bpm), systolic pressure (+18.4 ± 2.6 mmHg) but decreased supine LVET, LVET corrected for HR (LVETi) and QS2-time (all p  = 0.004). Despite similar HUT induced thoracic fluid shifts, reflected by similar thoracic impedance changes, HUT-induced adrenomedullin increases were minimal in epinephrine-supplemented men in comparison to controls (+8% vs. 42%). During HUT, epinephrine infusion decreased only the LVET ( p  = 0.039). Our findings confirm that short-term HUT increases plasma adrenomedullin. They further suggest that with increased supine epinephrine levels (epinephrine infusion clamping systolic arterial pressure at 120% control level), supine cardiac performance rises to a level similar to that during HUT, while adrenomedullin is still elevated with HUT. This might be in accordance with a ‘dampening’ role of adrenomedullin during catecholaminergic cardiovascular stimulation. As epinephrine is used as a drug to treat cardiac arrest and ventricular arrhythmias, our results may have important clinical/emergency resuscitation applications.