Department of Psychology, State University of New York at Buffalo, Buffalo, New York.
Alcohol Clin Exp Res. 2018 Mar;42(3):589-602. doi: 10.1111/acer.13581. Epub 2018 Jan 29.
Aversion to the orosensory properties of concentrated ethanol (EtOH) solutions is often cited as a primary barrier to initiation of drinking and may contribute to abstention. These aversive properties include gustatory processes which encompass both bitter-like taste qualities and trigeminal-mediated irritation. Chronic intermittent EtOH access (CIA) results in substantial and persistent increases in EtOH consumption, but the degree to which this facilitation involves sensory responding to EtOH and other bitter stimuli is currently undetermined.
Long-Evans rats were given brief-access licking tests designed to examine the immediate, taste-guided assessment of the palatability of EtOH and quinine solutions. Rats were assessed once in a naïve state and again following previous brief-access exposure, or following 4 weeks of CIA. The relationship between the sensitivity to the aversive orosensory properties of EtOH and quinine following EtOH access and the impact of antecedent quinine exposure on the acceptance of EtOH were determined in 2 parallel studies.
Both brief access to EtOH and 4-week CIA resulted in substantial rightward shifts in the concentration-response function of brief-access EtOH licking, indicating that EtOH exposure increased acceptance of the taste of EtOH. The initial sensitivity to the aversive orosensory properties of EtOH and quinine was positively correlated in naïve rats, such that rats that were initially more accepting of quinine were also more accepting of EtOH. Rats that sampled quinine immediately prior to tasting EtOH exhibited successive positive contrast in that they were more accepting of highly concentrated EtOH, relative to a water-control group.
Increased EtOH acceptance following exposure is, at least in part, facilitated by a decrease in its aversive sensory properties. Both long- and short-term access increase the palatability of the taste of EtOH in brief-access licking tests. Moreover, the sensitivity to the bitterness of quinine was predictive of acceptance of EtOH indicating some commonality in the sensory mechanisms that mediate the initial acceptance of the 2 stimuli. Accordingly, immediate prior exposure to quinine results in increased acceptance of EtOH, suggesting that successive positive contrast between oral stimuli may contribute to increased alcohol consumption.
人们常说，对浓乙醇（EtOH）溶液的味觉感官特性的反感是开始饮酒的主要障碍，并可能导致戒酒。这些令人反感的特性包括味觉过程，既包括苦味样的味道质量，也包括三叉神经介导的刺激。慢性间歇性乙醇摄入（CIA）会导致乙醇消耗的大量和持续增加，但目前尚不清楚这种促进作用在多大程度上涉及对乙醇和其他苦味刺激的感官反应。
长爪沙鼠进行了短暂访问舔食测试，旨在检查乙醇和奎宁溶液的可接受性的即时、味觉引导评估。大鼠在初次状态下评估一次，在先前短暂接触暴露后再次评估，或在 CIA 后 4 周评估。在两项平行研究中，确定了乙醇接触后对乙醇和奎宁的厌恶口腔感觉特性的敏感性与奎宁暴露对乙醇接受度的影响之间的关系。
短暂接触乙醇和 4 周 CIA 都导致短暂接触乙醇舔食的浓度-反应函数发生了实质性的右移，表明乙醇暴露增加了对乙醇味道的接受度。在初次接受测试的大鼠中，对乙醇和奎宁的厌恶口腔感觉特性的初始敏感性呈正相关，即最初对奎宁接受度较高的大鼠对乙醇的接受度也较高。在品尝乙醇之前立即品尝奎宁的大鼠在连续正对比中表现出对高度浓缩乙醇的接受度增加，与水对照相比。
暴露后乙醇接受度的增加至少部分是由于其厌恶的感官特性降低所致。长期和短期接触都会增加在短暂接触舔食测试中对乙醇味道的接受度。此外，对奎宁苦味的敏感性预测了对乙醇的接受度，表明介导对这两种刺激的初始接受的感官机制有一些共同性。因此，立即暴露于奎宁会导致对乙醇的接受度增加，这表明口腔刺激之间的连续正对比可能导致酒精摄入量增加。
