EFFECT OF TASTE & TRIGEMINAL STIMULATION ON NEUROENDOCRINE VALUES

目的：本研究的目的是确定味觉和/或三叉神经刺激是否对人类神经内分泌水平有生理影响。我们在本研究中测试的假设是，苦味物质或碳酸化作用通过刺激三叉神经或味觉刺激改变血液中应激激素的水平。如果这种刺激发生，它可能会对消瘦患者产生不利影响。不幸的是，患者服用的许多药物，例如艾滋病患者，都是非常苦的，可能会引起三叉神经/味觉刺激，可能会增加应激激素，并可能导致代谢率和消瘦。正在研究的神经内分泌参数是肾上腺素、去甲肾上腺素和皮质醇。对味觉和嗅觉感受器的化学感觉刺激发生在进食行为中，促使头部阶段的反应，包括唾液和胃液分泌增加，胰腺外分泌增加，胰岛素分泌增加，血液中游离脂肪酸水平下降。碳酸作用(如碳酸饮料中的碳酸饮料)，虽然不被认为是一种味道，但会刺激三叉神经。苦味物质还可以通过渗透到味觉细胞的胆脂膜以及细胞之间的紧密连接来刺激三叉神经，从而刺激自由神经末梢。方法：在这项研究中，受试者在30分钟的时间内进行筛查，并在筛查后至少一天在一次4个半小时的会议上进行测试。在筛查中记录病史和饮食记录，并签署知情同意书。在考试当天上午，受试者被允许进入CRU。然后，受试者将生理盐水锁在外周手臂静脉中。60分钟后，取基线血样。然后，10毫升的水被喷入受试者的嘴里，受试者挥动并吐痰。分别在刺激后5分钟、10分钟和25分钟采集血样。每个测试刺激之间有25分钟的休息时间。然后，以与对照刺激相同的方式测试三个测试刺激(水)，并在给药前立即以及给药后5、10和25分钟抽血。味觉刺激以固定的顺序递送，从最小到最强烈：水、碳酸水、苦水(Inviase)和辣椒素。分析每个血样的肾上腺素、去甲肾上腺素和皮质醇的血液浓度。每个受试者总共抽血16次，每次5毫升(每个受试者总共80毫升)。血液被离心，血浆被冷冻在-70oC直到化验。皮质醇的测定采用放射免疫法，儿茶酚胺的分离采用高效液相色谱法和电化学法。受试者的脉搏和血压在刺激前立即测量，并在刺激后25分钟测量。受试者对感知到的总体刺激强度和每个刺激的愉悦程度以及他们的情绪、警觉性和饥饿程度进行在线评分。在给予每种味觉刺激前后，比较肾上腺素、去甲肾上腺素和皮质醇的水平。结果：研究正在进行中。已经对8名受试者进行了检测，但尚未对血浆样本进行分析。未来计划：检测最终将扩大到艾滋病患者和老年人。

Purpose: The purpose of this study is to determine whether taste and/or trigeminal stimulation have a physiological effect on neuroendocrine levels in humans. The hypothesis we are testing in the present study is that bitter substances or carbonation alter the level of stress hormones in the blood through stimulation of trigeminal or taste stimulation. If this stimulation occurs, it could have adverse effects in patients with wasting. Unfortunately, many of the medications taken by patients, for example those with AIDS, are extremely bitter, and could cause trigeminal/taste stimulation that could increase stress hormones, and possibly metabolic rate and wasting. The neuroendocrine parameters being studied are epinephrine, norepinephrine, and cortisol. Chemosensory stimulation of the taste and smell receptors, which occurs during ingestive behavior, prompts cephalic phase responses which include increased salivation and gastric secretion, increased pancreatic exocrine secretion, increased secretion of insulin, and decreased blood levels of FFA. Carbonation (as in carbonated beverages), while not considered a taste, stimulates the trigeminal nerve. Bitter substances can also stimulate the trigeminal nerve by permeating through bilipid membranes of taste cells as well tight junctions between cells to stimulate free nerve endings. Methods: In this study subjects are screened in a 30-minute session and tested in one 4 1/2 hour session at least one day after the screening. Medical and dietary histories are taken and informed consents are signed at the screening. In the morning of the test session day, the subject is admitted to the CRU. The subject then has a saline lock placed in a peripheral arm vein. Sixty minutes later a baseline blood sample is taken. Then 10 ml of water is squirted into the subject's mouth, which he swishes and expectorates. Blood samples are taken at 5 minutes, 10 minutes, and 25 minutes after stimulus administration. There is a twenty-five minute break between each test stimulus. Three test stimuli are then tested in the same manner as the control stimulus (water) and blood draws are taken immediately before, and 5, 10, and 25 minutes after administration of the stimulus. The taste stimuli are delivered in a fixed order, from least to most intense: water, carbonated water, bitter water (Invirase), and capsaicin. The blood concentrations of epinephrine, norepinephrine, and cortisol are analyzed for each blood sample. Each subject has a total of 16 blood draws of 5 ml each (80 ml total per subject). Blood is centrifuged and the plasma is frozen at -70oC until assay. Cortisol is measured by radioimmunoassay, and catecholamines are separated by HPLC and quantitated electrochemically. The subject's pulse and blood pressure is taken immediately before stimulus administration, and 25 minutes after stimulus administration. Subjects rate the perceived overall intensity of the stimulus and the pleasantness of each stimulus, as well as their mood, alertness, and level of hunger on line scales. The levels of epinephrine, norepinephrine, and cortisol are compared before and after the administration of each taste stimulation. Results: The study is in progress. Eight subjects have been tested but plasma samples have not yet been analyzed. Future plans: The testing will ultimately be expanded to AIDS patients and the elderly.