Outbred rats differ in their preference for the artificial sweetener sucralose. Psychophysical assessments have shown that the taste of sucralose is differentially generalized to either sucrose or a sucrose-quinine (QHCl) mixture in sucralose preferers (SP) and sucralose avoiders (SA), respectively. It remains to be determined if these differences in the psychophysical assessment of the taste of sucralose are due to an insensitivity to any bitter-like taste component of sucralose in SP or reduced sensitivity to a sweet-like component in SA that may mask any putative aversive side-taste in SP. Here, we exploited the proposed chemotopic organization of the rostral nucleus of the solitary tract (rNTS) to further parse out the root differences in the perception of the salient taste qualities of sucralose using Fos-like immunoreactivity (FLI) to approximate neural activation following intraoral delivery of sucrose, QHCl, and sucralose solutions in previously categorized SA and SP. First, we confirmed previous reports that the medial third of the NTS is primarily responsive to intraoral infusions of the bitter taste stimulus QHCl while sucrose produces a more diffuse pattern of FLI. Upon comparing the FLI generated by intraoral sucralose, we found that the pattern in SA was indistinguishable from that of QHCl while SP displayed a pattern of FLI more representative of a sucrose-QHCl mixture. We conclude that SA, relative to SP, may be less sensitive to the sucrose-like properties of sucralose and that an enhanced sensitivity to these sucrose-like qualities may mask a QHCl-like quality in SP.

中文翻译：

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孤束核内表达的 Fos 样免疫反应模式与刺激物味觉质量的个体差异有关

远交大鼠对人造甜味剂三氯蔗糖的偏好不同。心理物理评估表明，三氯蔗糖的味道分别在三氯蔗糖偏爱者 (SP) 和三氯蔗糖回避者 (SA) 中不同地概括为蔗糖或蔗糖-奎宁 (QHCl) 混合物。三氯蔗糖味道的心理物理评估的这些差异是否是由于对 SP 中三氯蔗糖的任何苦味成分不敏感或对 SA 中可能掩盖任何推定厌恶的甜味成分的敏感性降低，仍有待确定SP的副食。这里，我们利用所提出的孤束喙核（rNTS）的趋化组织来进一步解析出对三氯蔗糖显着味道品质感知的根本差异，使用类Fos免疫反应性（FLI）来近似在口内递送后的神经激活以前分类的 SA 和 SP 中的蔗糖、QHCl 和三氯蔗糖溶液。首先，我们证实了之前的报道，即 NTS 的内侧三分之一主要对口内输注苦味刺激 QHCl 有反应，而蔗糖会产生更分散的 FLI 模式。在比较口腔内三氯蔗糖产生的 FLI 后，我们发现 SA 中的模式与 QHCl 的模式无法区分，而 SP 显示的 FLI 模式更能代表蔗糖-QHCl 混合物。我们得出结论，SA，相对于 SP，