Mumford G K, Evans S M, Kaminski B J, Preston K L, Sannerud C A, Silverman K, Griffiths R R
Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine, Baltimore, MD 21224.
Psychopharmacology (Berl). 1994 Jun;115(1-2):1-8. doi: 10.1007/BF02244744.
Theobromine versus placebo discrimination and caffeine versus placebo discrimination were studied in two consecutive experiments in seven volunteers who abstained from methylxanthines. Daily sessions involved PO double-blind ingestion of two sets of capsules sequentially, one of which contained drug and the other placebo. Subjects attempted to identify, and were later informed, which set of capsules contained the drug. In each experiment subjects were exposed to progressively lower doses. Five subjects acquired the theobromine discrimination; the lowest dose discriminated ranged from 100 to 560 mg. All seven subjects acquired the caffeine discrimination; the lowest dose discriminated ranged from 1.8 to 178 mg. A final experiment evaluated subjective effect ratings following 560 mg theobromine, 178 mg caffeine and placebo, which were administered double-blind in capsules once daily, five times each in mixed sequence. Caffeine produced changes in both group and individual ratings (e.g. increased well-being, energy, social disposition and alert). Theobromine did not produce changes in group ratings but changed ratings in some subjects. Across subjects, sensitivity to caffeine discriminative effects in the discrimination experiment correlated significantly with the number and magnitude of caffeine subjective effects in the final experiment. This study documents modest discriminative effects of theobromine in humans, but the basis of the discrimination is unclear. This study suggests that commonly consumed cocoa products contain behaviorally active doses of caffeine and possibly theobromine.
在七名戒食甲基黄嘌呤的志愿者身上进行了两项连续实验，研究了可可碱与安慰剂的辨别以及咖啡因与安慰剂的辨别。每日实验环节包括口服双盲法依次摄入两组胶囊，其中一组含有药物，另一组为安慰剂。受试者尝试辨别并随后被告知哪组胶囊含有药物。在每个实验中，受试者接触的剂量逐渐降低。五名受试者学会了辨别可可碱；辨别出的最低剂量范围为100至560毫克。所有七名受试者都学会了辨别咖啡因；辨别出的最低剂量范围为1.8至178毫克。最后一项实验评估了在双盲条件下，每日一次、每次五剂按混合顺序服用560毫克可可碱、178毫克咖啡因和安慰剂后的主观效果评分。咖啡因使群体评分和个体评分都发生了变化（例如，幸福感、精力、社交倾向和警觉性增强）。可可碱没有使群体评分发生变化，但在一些受试者中改变了评分。在所有受试者中，辨别实验中对咖啡因辨别效果的敏感性与最后一项实验中咖啡因主观效果的数量和程度显著相关。本研究记录了可可碱在人体中的适度辨别效果，但其辨别的基础尚不清楚。本研究表明，常见的可可制品含有具有行为活性剂量的咖啡因，可能还有可可碱。
