Inactivation of the ventral hippocampus facilitates the attenuation of odor neophobia in rats
Inactivation of the ventral hippocampus facilitates the attenuation of odor neophobia in rats
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DOI：
10.1016/j.bbr.2020.113077
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发表时间：
2021-03-05
影响因子：
2.7
通讯作者：
Yasoshima，Yasunobu
中科院分区：
文献类型：
--
作者：
Shinohara，Keisuke;Yasoshima，Yasunobu
食物新恐惧症是在啮齿动物身上观察到的一种行为，涉及减少消费一种新的食物或饮料。在没有摄入后的负面后果的情况下，摄入量随着暴露(新恐惧症的减轻)而增加，这被视为一种关联的安全记忆。嗅觉和味觉是形成食物偏好所必需的感觉方式。然而，人们对食物相关气味刺激产生新恐惧症的神经机制知之甚少。在本研究中，我们使用一种γ-氨基丁酸A受体激动剂，观察了腹侧海马区(VHPC)的药理失活对口服溶液的大鼠新恐惧症的影响。制备了杏仁味(苯甲醛)和甜味(糖精)两种不同类型的溶液。在结果中，在第一次嗅觉和味觉暴露之前，在双侧vHPC内微量注射蝇草酚并没有改变大鼠对每种刺激的新的恐惧症反应。然而，在第二种气味而不是味觉的暴露中，注射蝇草酚的大鼠表现出比对照组大鼠更高的消耗量，这表明vHPC的失活有助于减轻气味新恐惧症。另一方面，在第一次气味和味觉暴露后，在vHPC内微量注射蝇草酚并不利于第二次暴露时的消费。这些结果表明，在口服一种新的气味而不是味觉的溶液时，vHPC内的神经激活在随后的新恐惧症的缓解中起到了抑制作用。
Food neophobia is a behavior observed in rodents involving reduced consumption of a novel food or drink. In the absence of negative post-ingestive consequences, consumption increases with exposure (attenuation of neophobia), which is seen as an associative safe memory. Olfaction and gustation are sensory modalities essential for the development of a food preference. However, little is known about the neural mechanisms underlying neophobia to a food-related odor stimulus. In the present study, we examined the effect of pharmacological inactivation of the ventral hippocampus (vHPC) on neophobia to orally consumed solutions in rats using muscimol, a gamma aminobutyric acid type A receptor agonist. Two different types of solutions, almond odor (benzaldehyde) and sweet taste (saccharin), were prepared. In the results, microinjections of muscimol into the bilateral vHPC before the first odor and taste exposures did not alter the neophobic reactions of the rats to each stimulus. However, in the second odor, but not taste, exposure, the muscimol-injected rats showed higher consumption in comparison to that observed in the control rats, suggesting that the vHPC inactivation facilitates the attenuation of odor neophobia. On the other hand, intra-vHPC muscimol microinjections after the first odor and taste exposures did not facilitate consumption at the second exposures. These results indicate that neural activations within vHPC during orally consuming a novel odor, but not taste, solution play an inhibitory role in the subsequent attenuation of neophobia.