Residual Chemosensory Capabilities in Double P2X2/P2X3 Purinergic Receptor Null Mice: Intraoral or Postingestive Detection?
Residual Chemosensory Capabilities in Double P2X2/P2X3 Purinergic Receptor Null Mice: Intraoral or Postingestive Detection?
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DOI：
10.1093/chemse/bjp069
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发表时间：
2009-11-01
期刊：
影响因子：
3.5
通讯作者：
Finger, Thomas E.
中科院分区：
文献类型：
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作者：
Hallock, Robert M.;Tatangelo, Marco;Finger, Thomas E.
缺乏嘌呤能受体 P2X2 和 P2X3 (P2X2/P2X3(Dbl-/-)) 的小鼠，在鼓索和舌咽神经中基本上不表现出促味剂诱发的活性，并且在长期摄入实验中测得促味剂诱发的行为显着丧失。为了评估这些 P2X2/P2X3(Dbl-/-) 小鼠中残留的化学驱动行为是否归因于化合物的食后检测或口咽检测，我们使用短暂访问舔液计测试来评估 P2X2/P2X3(Dbl-/-) 动物的行为能力。 P2X2/P2X3(Dbl-/-) 小鼠在 24 小时、2 瓶偏好测试中表现出对高水平（10 mM 奎宁和 10-30 mM 苯甲酸地那铵）经典“苦”味刺激的回避，但在舔液计测试中对这些物质的回避程度最低，表明摄入测试中的强烈回避很大程度上是由口后化学传感器介导的。同样，P2X2/P2X3(Dbl-/-) 小鼠在长期摄入测试中 1 M 蔗糖消耗量的增加并未反映在舔液计测试中蔗糖消耗量的增加，这表明这些小鼠中的蔗糖检测是由食后后果介导的。相比之下，在简短的访问测试中，P2X2/P2X3(Dbl-/-)小鼠避免使用与野生型小鼠相同浓度的柠檬酸和盐酸，这表明这些弱酸激活口咽化学感受器。
Mice lacking the purinergic receptors, P2X2 and P2X3 (P2X2/P2X3(Dbl-/-)), exhibit essentially no tastant-evoked activity in the chorda tympani and glossopharyngeal nerves and substantial loss of tastant-evoked behavior as measured in long-term intake experiments. To assess whether the residual chemically driven behaviors in these P2X2/P2X3(Dbl-/-) mice were attributable to postingestive detection or oropharyngeal detection of the compounds, we used brief access lickometer tests to assess the behavioral capabilities of the P2X2/P2X3(Dbl-/-) animals. The P2X2/P2X3(Dbl-/-) mice showed avoidance to high levels (10 mM quinine and 10-30 mM denatonium benzoate) of classical "bitter"-tasting stimuli in 24-h, 2-bottle preference tests but minimal avoidance of these substances in the lickometer tests, suggesting that the strong avoidance in the intake tests was largely mediated by post-oral chemosensors. Similarly, increases in consumption of 1 M sucrose by P2X2/P2X3(Dbl-/-) mice in long-term intake tests were not mirrored by increases in consumption of sucrose in lickometer tests, suggesting that sucrose detection in these mice is mediated by postingestive consequences. In contrast, in brief access tests, P2X2/P2X3(Dbl-/-) mice avoided citric acid and hydrochloric acid at the same concentrations as their wild-type counterparts, indicating that these weak acids activate oropharyngeal chemoreceptors.