Role of endogenous opioids in syncope induced by head-up tilt test and its relationship with isoproterenol-dependent and isoproterenol-independent neurally-mediated syncope

• Published in: International journal of cardiology 1998-12, Vol.67 (3), p.211-218
• Main Authors: Pérez-Paredes, Matı́as, Picó-Aracil, Francisco, Fuentes-Jiménez, Teo, Sánchez-Villanueva, José G, Expósito-Ordoñez, Elena, Gonzálvez-Ortega, Manuel, González-Caballero, Eva, Nicolás-Garcia, F, Nuño de la Rosa, José A, Ruiz-Ros, José A, Ruipérez-Abizanda, Juan A
• Format: Article
• Language: English
• Subjects: Adolescent; Adrenergic beta-Agonists - administration & dosage; Adult; Aged; beta-Endorphin - blood; beta-Endorphin - drug effects; Biological and medical sciences; Child; Endogenous opioids; Female; Head-up tilt test; Headache. Facial pains. Syncopes. Epilepsia. Intracranial hypertension. Brain oedema. Cerebral palsy; Humans; Isoproterenol - administration & dosage; Male; Medical sciences; Middle Aged; Naloxone; Naloxone - pharmacology; Naloxone - therapeutic use; Narcotic Antagonists - pharmacology; Narcotic Antagonists - therapeutic use; Nervous system (semeiology, syndromes); Neurology; Opioid Peptides - physiology; Pathophysiology; Syncope, Vasovagal - chemically induced; Syncope, Vasovagal - physiopathology; Syncope, Vasovagal - prevention & control; Tilt-Table Test; Vasovagal syncope
• ISSN: 0167-5273; 1874-1754
• DOI: 10.1016/S0167-5273(98)00220-4

This study was designed to evaluate the role of endogenous opioids in neurally-mediated syncope. Head-up tilt test was performed on 35 patients with syncope of unknown origin. Plasma β-endorphin was measured (1) at baseline, (2) at the end of tilt test or at time of syncope, (3) 15 min before isoproterenol-test, (4) at the end of the isoproterenol-test or at time of syncope. Subjects with a positive tilt testing showed a larger rise in plasma β-endorphin concentrations at time of syncope (baseline 13.7±8.0 vs. syncope 41.4±26.4 pmol l −1; P