Hughes Robert N, Hancock Nicola J, Henwood Gina A, Rapley Susan A
Department of Psychology, University of Canterbury, Christchurch 8140, New Zealand.
Department of Psychology, University of Canterbury, Christchurch 8140, New Zealand.
Behav Brain Res. 2014 Sep 1;271:7-15. doi: 10.1016/j.bbr.2014.05.038. Epub 2014 May 27.
Male and female PVG/c rats were observed in an open field (OF) and an elevated plus maze (EPM) either with or without a bright light stressor (600-692 lx) following an intraperitoneal injection of saline, 25 or 50mg/kg of caffeine. One week later, the same rats were observed under the same drug and lighting conditions but in the opposite apparatus to that experienced earlier. Either the higher or both doses of caffeine decreased anxiety as indicated by increased OF rearing and decreased grooming, immobility and corner occupancy (in the presence of bright light). A similar interpretation applied to caffeine-related increased entries into and observations in the EPM open arms for males only, and increased entries into the open arms for females alone in the presence of bright light. Bright light increased anxiety as shown by longer latencies of emergence into the OF and decreased ambulation and, for males only, decreased center occupancy and increased corner occupancy. Fewer entries into the open arms in the presence of bright light for females only also suggested heightened anxiety. Apart from one OF and one EPM measure, bright light did not appear to markedly influence the effects of caffeine which were concluded to be primarily anxiolytic, with males being more affected than females. Although the central mechanisms responsible for caffeine's anxiolytic action remain to be established, it is possible that antagonism of A2A adenosine receptors might somehow be involved.
对雄性和雌性PVG/c大鼠进行观察，在腹腔注射生理盐水、25或50mg/kg咖啡因后，分别在旷场（OF）和高架十字迷宫（EPM）中，有或没有强光应激源（600 - 692勒克斯）的情况下进行观察。一周后，同样的大鼠在相同的药物和光照条件下，但在与之前不同的实验装置中进行观察。较高剂量或两种剂量的咖啡因均可降低焦虑，表现为旷场中竖毛行为增加，梳理、静止不动和角落停留行为减少（在有强光的情况下）。类似的解释也适用于咖啡因相关的情况，即仅对雄性而言，进入EPM开放臂的次数增加以及在开放臂中的观察时间增加，而在有强光的情况下，仅对雌性而言，进入开放臂的次数增加。强光会增加焦虑，表现为进入旷场的潜伏期延长、行走减少，并且仅对雄性而言，中央区域停留减少、角落停留增加。仅对雌性而言，在有强光的情况下进入开放臂的次数减少也表明焦虑加剧。除了一项旷场和一项高架十字迷宫测量外，强光似乎并未显著影响咖啡因的作用，咖啡因的作用主要被认为是抗焦虑的，雄性比雌性受影响更大。尽管咖啡因抗焦虑作用的中枢机制仍有待确定，但A2A腺苷受体的拮抗作用可能在某种程度上参与其中。
