High-Sugar, but Not High-Fat, Food Activates Supraoptic Nucleus Neurons in the Male Rat
High-Sugar, but Not High-Fat, Food Activates Supraoptic Nucleus Neurons in the Male Rat
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DOI：
10.1210/en.2016-1640
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发表时间：
2017-07-01
期刊：
影响因子：
4.8
通讯作者：
Menzies, John
中科院分区：
文献类型：
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作者：
Hume, Catherine;Sabatier, Nancy;Menzies, John
催产素是一种有效的催产素，被认为在饱腹感信号中发挥作用。我们开发了大鼠模型，研究催产素神经元的活动，自愿消费或口服灌胃的食物，使用c-Fos免疫组织化学和体内电生理学。使用c-Fos表达作为神经激活的间接标记，我们发现，表达c-Fos的大细胞催产素神经元的百分比增加与自愿消费的甜炼乳（SCM）。为了模拟食物在胃中的作用，我们用SCM灌胃麻醉大鼠。结果显示，大鼠视上核和室旁核大细胞催产素免疫反应阳性神经元表达c-Fos的比例随SCM灌胃而增加，但随胃扩张而增加。为了进一步研究视上核的活动，我们从SON神经元进行了体内电生理记录，其中麻醉大鼠灌胃SCM或单一乳膏。药理学鉴定的催产素神经元响应SCM管饲与线性，成比例，持续增加的放电率，但奶油管饲导致短暂的放电率降低。SCM灌胃后血糖升高，但奶油灌胃后血糖未升高。血浆渗透压摩尔浓度和血浆钠始终保持不变。我们发现，在胃中对高糖而非高脂肪食物的反应中，催产素神经元的活性增加。这似乎不是胃扩张或渗透压变化的结果。我们的数据表明，在胃中具有不同宏量营养素谱的特定食物的存在差异调节催产素神经元的活性。
Oxytocin is a potent anorexigen and is believed to have a role in satiety signaling. We developed rat models to study the activity of oxytocin neurons in response to voluntary consumption or oral gavage of foods using c-Fos immunohistochemistry and in vivo electrophysiology. Using c-Fos expression as an indirect marker of neural activation, we showed that the percentage of magnocellular oxytocin neurons expressing c-Fos increased with voluntary consumption of sweetened condensed milk (SCM). To model the effect of food in the stomach, we gavaged anesthetized rats with SCM. The percentage of supraoptic nucleus and paraventricular nucleus magnocellular oxytocin-immunoreactive neurons expressing c-Fos increased with SCM gavage but not with gastric distention. To further examine the activity of the supraoptic nucleus, we made in vivo electrophysiological recordings from SON neurons, where anesthetized rats were gavaged with SCM or single cream. Pharmacologically identified oxytocin neurons responded to SCM gavage with a linear, proportional, and sustained increase in firing rate, but cream gavage resulted in a transient reduction in firing rate. Blood glucose increased after SCM gavage but not cream gavage. Plasma osmolarity and plasma sodium were unchanged throughout. We show that in response to high-sugar, but not high-fat, food in the stomach, there is an increase in the activity of oxytocin neurons. This does not appear to be a consequence of stomach distention or changes in osmotic pressure. Our data suggest that the presence of specific foods with different macronutrient profiles in the stomach differentially regulates the activity of oxytocin neurons.