Department of Neuroscience and Physiology, State University of New York Upstate Medical University, Syracuse, New York, USA.
Behav Brain Funct. 2009 Jun 4;5:23. doi: 10.1186/1744-9081-5-23.
The social transmission of food preference paradigm centers on the finding that observers obtain dietary information through olfactory cues on the breath of a demonstrator peer that has ingested a novel substance. This phenomenon plays a role in ethanol acceptability. Historically, studies using this technique have focused on observer animals in order to study the social transmission process. With respect to ethanol, studies of acute intoxication have shown that the pharmacologic properties of ethanol and hematogenic olfaction can influence the subsequent ethanol odor-mediated responses of the intoxicated animals. These acute studies, however, demonstrate odor aversion. The present study compared the effect of adolescent ethanol exposure, via the social transmission paradigm, on the behavioral response to ethanol odor in both observer and demonstrator animals in adolescence (postnatal day (P) 37) and the persistence of these effects into adulthood (P90).
Beginning on P29, naïve rats received four ethanol or water exposures: one every 48 hours through either direct intragastric infusion or social interaction with an infused peer. The reflexive sniffing response of observers and demonstrators to ethanol odor was tested at P37 or P90 using whole-body plethysmography.
The behavioral response of adolescent ethanol observers and demonstrators significantly differed between themselves and from their respective water controls. Ethanol and water observers both displayed a greater response to ethanol odor than their respective demonstrator counterparts. Compared to controls, both modes of ethanol exposure produced similar magnitudes of enhancement. At P90, both forms of exposure displayed similar responses to ethanol odor and similar magnitudes of enhancement. Only demonstrators displayed equivalent enhanced responses in both sexes.
In contrast to previous studies showing odor aversion following acute ethanol intoxication, within the context of the social transmission paradigm, adolescent demonstrators like observers showed an enhanced behavioral response to ethanol odor. The differential enhanced odor response between observers and demonstrators, despite similar net enhancements relative to controls, suggests the presence of a stress effect from the infusion technique. This finding contrasts previous suggestions that intragastric infusions create minimal stress: an important consideration when conducting ethanol research. This stress effect appears to ameliorate by adulthood.
食物偏好的社会传递范式的中心思想是，观察到的动物通过嗅闻示范者同伴吸入新奇物质后呼出的气味来获取饮食信息。这一现象在乙醇接受度中发挥了作用。从历史上看，使用这种技术的研究集中在观察动物身上，以研究社会传递过程。关于乙醇，急性中毒研究表明，乙醇的药理特性和血液嗅觉会影响随后中毒动物对乙醇气味的反应。然而，这些急性研究表明存在气味回避。本研究通过社会传递范式比较了青春期暴露于乙醇对青春期（出生后第 37 天）观察动物和示范动物对乙醇气味行为反应的影响，以及这些影响在成年期（第 90 天）的持续时间。
从第 29 天开始，新生大鼠接受 4 次乙醇或水暴露：通过直接胃内输注或与输注同伴进行社会互动，每 48 小时一次。在第 37 天或第 90 天，使用全身 plethysmography 测试观察动物和示范动物对乙醇气味的反射性嗅探反应。
青春期乙醇观察动物和示范动物的行为反应与各自的水对照动物明显不同。乙醇和水观察动物对乙醇气味的反应均大于各自的示范动物。与对照组相比，两种乙醇暴露方式均产生了相似程度的增强。在第 90 天，两种暴露方式对乙醇气味的反应相似，增强程度也相似。只有示范动物在两种性别中均显示出同等的增强反应。
与先前研究表明急性乙醇中毒后出现气味回避的研究结果相反，在社会传递范式中，青春期示范动物和观察动物对乙醇气味表现出增强的行为反应。观察动物和示范动物之间存在不同的增强气味反应，尽管相对于对照组有相似的净增强，但这表明输注技术存在应激效应。这一发现与之前的观点相矛盾，即胃内输注造成的压力很小：在进行乙醇研究时，这是一个重要的考虑因素。这种应激效应似乎在成年期得到缓解。
