Human brain metabolic response to caffeine and the effects of tolerance.
Human brain metabolic response to caffeine and the effects of tolerance.
复制标题
人脑对咖啡因的代谢反应和耐受性的影响。
DOI：
10.1176/ajp.156.2.229
复制
发表时间：
1999
期刊：
影响因子：
--
通讯作者：
Posse,S
中科院分区：
文献类型：
--
作者：
Dager,SR;Layton,ME;Strauss,W;Richards,TL;Heide,A;Friedman,SD;Artru,AA;Hayes,CE;Posse,S
目的由于有关咖啡因对人脑代谢影响的信息有限，作者应用快速质子回波平面光谱成像技术来动态测量咖啡因摄入的区域大脑代谢反应。他们专门测量了由于咖啡因刺激糖酵解和减少脑血流量的综合影响而引起的脑乳酸变化。 方法 对 9 名重度咖啡因使用者和 9 名咖啡因不耐受者进行了基线研究，然后在摄入柠檬酸咖啡因（10 毫克/千克）后 1 小时内进行了研究，这些人之前因相关的焦虑和不适的生理唤醒而停止或大幅减少了含咖啡因产品的使用。为了评估咖啡因耐受性的状态特征贡献和影响，五名咖啡因使用者在休息 1 至 2 个月的咖啡因假期后接受了重新研究。 结果 不耐受咖啡因的个体（而非经常喝咖啡的人）因摄入咖啡因而经历了严重的心理和生理痛苦。仅在咖啡因不耐受的受试者中观察到整体和区域特定脑乳酸显着增加。经常喝咖啡因的人在咖啡因假期后重新接触咖啡因，几乎没有或没有不良临床反应，但脑乳酸显着升高，其幅度与咖啡因不耐受组观察到的水平相似。结论这些结果为停止咖啡因后人脑中咖啡因耐受性的丧失提供了直接证据，并提示了咖啡因不耐受现象的机制，而不是其对脑乳酸升高的代谢影响。
OBJECTIVESince there is limited information concerning caffeine’s metabolic effects on the human brain, the authors applied a rapid proton echo-planar spectroscopic imaging technique to dynamically measure regional brain metabolic responses to caffeine ingestion. They specifically measured changes in brain lactate due to the combined effects of caffeine’s stimulation of glycolysis and reduction of cerebral blood flow.METHODNine heavy caffeine users and nine caffeine-intolerant individuals, who had previously discontinued or substantially curtailed use of caffeinated products because of associated anxiety and discomforting physiological arousal, were studied at baseline and then during 1 hour following ingestion of caffeine citrate (10 mg/kg). To assess state-trait contributions and the effects of caffeine tolerance, five of the caffeine users were restudied after a 1- to 2-month caffeine holiday.RESULTSThe caffeine-intolerant individuals, but not the regular caffeine users, experienced substantial psychological and physiological distress in response to caffeine ingestion. Significant increases in global and regionally specific brain lactate were observed only among the caffeine-intolerant subjects. Reexposure of the regular caffeine users to caffeine after a caffeine holiday resulted in little or no adverse clinical reaction but significant rises in brain lactate which were of a magnitude similar to that observed for the caffeine-intolerant group.CONCLUSIONSThese results provide direct evidence for the loss of caffeine tolerance in the human brain subsequent to caffeine discontinuation and suggest mechanisms for the phenomenon of caffeine intolerance other than its metabolic effects on elevating brain lactate.