Garrett B E, Holtzman S G
Department of Pharmacology, Emory University, Atlanta, GA 30322.
Pharmacol Biochem Behav. 1994 Jan;47(1):89-94. doi: 10.1016/0091-3057(94)90115-5.
The mechanism of action for the behavioral stimulant effects of caffeine has been extensively studied, but results have been ambiguous and inconsistent. The present study examined the role of dopamine in caffeine-induced stimulation of locomotor activity in rats. d-Amphetamine was also tested for comparison. Locomotor activity of male Sprague-Dawley rats (300-350 g) was measured using two-channel electronic activity monitors. Activity counts were recorded for 30 min following a 30-min pretreatment with either caffeine (3.0-100 mg/kg, IP) or d-amphetamine (0.1-3.0 mg/kg, IP) alone and in combination with the D1 dopamine antagonist SCH23390 (0.01 and 0.003 mg/kg, SC) or the D2 dopamine antagonists sulpiride (30 mg/kg, SC) or eticlopride (0.03 mg/kg, SC). Caffeine and d-amphetamine dose dependently increased locomotor activity. This effect of both caffeine and d-amphetamine was blocked by SCH23390 as well as by eticlopride. Sulpiride blocked the stimulatory effects of caffeine but not d-amphetamine. These results suggest that the locomotor stimulant effect of caffeine, like that of d-amphetamine, is mediated through dopaminergic systems; both D1 and D2 receptors appear to be involved.
咖啡因行为刺激作用的作用机制已得到广泛研究，但结果一直含糊不清且不一致。本研究考察了多巴胺在咖啡因诱导大鼠运动活动增强中的作用。同时对右旋苯丙胺进行了测试以作比较。使用双通道电子活动监测仪测量雄性Sprague-Dawley大鼠（300 - 350 g）的运动活动。在分别用咖啡因（3.0 - 100 mg/kg，腹腔注射）或右旋苯丙胺（0.1 - 3.0 mg/kg，腹腔注射）单独预处理30分钟后，以及与D1多巴胺拮抗剂SCH23390（0.01和0.003 mg/kg，皮下注射）或D2多巴胺拮抗剂舒必利（30 mg/kg，皮下注射）或依托必利（0.03 mg/kg，皮下注射）联合预处理30分钟后，记录30分钟的活动计数。咖啡因和右旋苯丙胺均剂量依赖性地增加运动活动。SCH23390以及依托必利均可阻断咖啡因和右旋苯丙胺的这种作用。舒必利可阻断咖啡因的刺激作用，但不能阻断右旋苯丙胺的刺激作用。这些结果表明，咖啡因的运动刺激作用与右旋苯丙胺类似，是通过多巴胺能系统介导的；D1和D2受体似乎均参与其中。
