Ishii Y, Blundell J E, Halford J C G, Rodgers R J
Behavioural Pharmacology Laboratory, School of Psychology, University of Leeds, LS2 9JT, Leeds, UK.
Physiol Behav. 2003 Oct;80(1):37-47. doi: 10.1016/s0031-9384(03)00207-5.
Food intake is influenced not only by nutritional status but also by diverse environmental factors. Indeed, a unique quality of food reward is its strong modulation by palatability cues, such as taste, with animals generally preferring diets that are sweet and avoiding those that are either bitter or sour. As appetite suppressants (including those currently in development) could alter food intake by modifying taste sensitivity and/or palatability, the aim of the present study was to characterise the influence of taste adulteration on the normal structure of feeding behaviour, i.e., the behavioural satiety sequence (BSS). Adult male rats were initially habituated both to the basic test diet (mash) and the test arena. Following stabilisation of basal intake, a continuous monitoring technique was used to profile behaviour in weekly 1-h sessions during which the animals were presented, in counterbalanced order, with the basic diet (control) or one of four taste-adulterated variants (0.015% quinine, 0.04% quinine, 0.2% saccharin, 0.3% saccharin). Food intake was strongly suppressed by the higher quinine concentration but was not significantly altered by any of the other additives. Behavioural analysis revealed that this anorectic-like response to 0.04% quinine-adulterated food was associated with a significant reduction in the peak feeding response, highly atypical intermittent food sampling/digging and the virtual absence of resting behaviour. Importantly, this pattern of behavioural change is readily distinguishable from those seen in response to other manipulations that reduce intake, including selective anorectics, sedatives and psychostimulants. Despite the lack of significant effect on food intake or the duration of feeding behaviour, dietary adulteration with 0.015% quinine (and, to a lesser degree, 0.3% saccharin) produced some effects on behavioural structure/time course consistent with a mild aversive response, i.e., bouts of midsession food sampling and a delay in the transition from eating to resting. Data are discussed in relation to the specific behavioural signature to quinine-induced anorexia and its potential utility in identifying appetite suppressants that may modify intake via changes in taste sensitivity and/or palatability.
食物摄入量不仅受营养状况影响，还受多种环境因素影响。事实上，食物奖赏的一个独特特性是其受适口性线索（如味道）的强烈调节，动物通常更喜欢甜味食物，而避免苦味或酸味食物。由于食欲抑制剂（包括目前正在研发的那些）可能通过改变味觉敏感性和/或适口性来改变食物摄入量，本研究的目的是描述味觉掺假对正常进食行为结构（即行为饱腹感序列，BSS）的影响。成年雄性大鼠最初要适应基础测试饮食（糊状食物）和测试环境。在基础摄入量稳定后，采用连续监测技术，在每周1小时的时间段内记录行为，在此期间，给动物按平衡顺序喂食基础饮食（对照）或四种味觉掺假变体之一（0.015%奎宁、0.04%奎宁、0.2%糖精、0.3%糖精）。较高浓度的奎宁强烈抑制食物摄入，但其他添加剂均未显著改变食物摄入量。行为分析表明，对0.04%奎宁掺假食物的这种厌食样反应与峰值进食反应显著降低、高度非典型的间歇性食物采样/挖掘以及几乎没有休息行为有关。重要的是，这种行为变化模式很容易与因其他减少摄入量的操作（包括选择性厌食剂、镇静剂和精神兴奋剂）而出现的模式区分开来。尽管对食物摄入量或进食行为持续时间没有显著影响，但用0.015%奎宁（以及在较小程度上用0.3%糖精）进行饮食掺假对行为结构/时间进程产生了一些与轻度厌恶反应一致的影响，即中期食物采样发作以及从进食到休息的转变延迟。将结合奎宁诱导厌食的特定行为特征及其在识别可能通过改变味觉敏感性和/或适口性来改变摄入量的食欲抑制剂方面的潜在效用对数据进行讨论。
