The Role of Adrenaline in Neurally Mediated Syncope

晕厥是与生活质量差相关的常见问题。大多数患者患有神经介导性晕厥（NMS），其病理生理学知之甚少。我们评估了NMS患者（n=8，年龄39±11岁，BMI 24±4 kg/m2）和健康受试者（n=10，年龄30±7岁，BMI 25±3 kg/m2）的心血管自主神经功能以及α2B肾上腺素受体（α2B-AR）的遗传多态性。对每名受试者进行标准自主神经功能测试（AFT）和头高位倾斜（HUT）测试。在仰卧位30分钟后和HUT结束时测量血浆儿茶酚胺（CAT）、肾素和醛固酮。24小时尿液采集用于测量钠和CAT排泄。鉴定了α2B AR中存在的谷氨酸（Glu）重复序列（Glu 12或Glu 9，氨基酸残基301-303）的多态性。我们在NMS患者和健康对照中有3名Glu 12/12，12名Glu 12/9和2名Glu 9/9受试者;所有NMS患者均显示Glu 12/9。晕厥受试者有Glu 12/12或Glu 12/9，而Glu 9/9受试者没有直立症状（OS）。因此，我们将使用NMS患者和非NMS患者研究这种多态性作为直立性应激时人类血管反应标志物的可能性

yncope is a common problem associated with a poor quality of life. A majority of patients suffer from neurally mediated syncope (NMS), which is poorly understood in its pathophysiology. We evaluated cardiovascular autonomic functions as well as genetic polymorphisms of the α2B adrenoceptors (α2B-AR) predisposed to NMS patients (n=8, age 39±11 year, BMI 24±4 kg/m2) and healthy subjects (n=10, age 30±7 year, BMI 25±3 kg/m2). The standard autonomic function test (AFT) and head-up tilt (HUT) test were performed on each subject. Plasma catecholamines (CATs), renin, and aldosterone were measured after 30 minutes supine and at the end of the HUT. Twenty-four-hour urine collections were used to measure sodium and CATs excretion. A polymorphism of glutamic acid (Glu) repeats (Glu 12 or Glu 9, amino acids residues 301-303) present in the α2B AR was identified. We had three Glu 12/12, twelve Glu 12/9, and two Glu 9/9 subjects among the NMS patients and healthy controls; all of the NMS patients showed Glu 12/9. Syncopal subjects had Glu12/12 or Glu12/9 whereas subjects who had Glu9/9 did not have orthostatic symptom (OS). Therefore, we will investigate the possibility of this polymorphism as a marker of human vasomotor responses during orthostatic stress using subjects with and without NMS