Ghrelin is an orexigenic agonist that acts directly on neurons in the hypothalamus, controlling appetite and energy balance. Although its role in appetite-associated neurons has been described, the relationship between peripheral ghrelin stimulation and oxytocin expression in the paraventricular nucleus is not fully understood. We evaluated the suppressive function of ghrelin in oxytocin-positive paraventricular nucleus neurons in ovariectomized C57BL/6 mice 2 h after ghrelin injection. The results showed that, in intact mice, peripheral ghrelin stimulation activated estrogen receptor alpha-expressing neurons during the estrous cycle and that agouti-related peptide mRNA expression was remarkably increased. Agouti-related peptide neuron axons co-localized with oxytocin neurons in the paraventricular nucleus. Moreover, the response of oxytocin-positive paraventricular nucleus neurons to ghrelin was suppressed in the proestrus period, while ghrelin decreased the serum concentration of estradiol in the proestrus phase. These data suggest that ghrelin may suppress oxytocin-positive neuron expression via the arcuate nucleus agouti-related peptide circuit, with the possible influence of estradiol in the murine estrous cycle. Unraveling the mechanism of ghrelin-induced oxytocin expression in the hypothalamus paraventricular nucleus broadens the horizon for ghrelin-related appetite research.

中文翻译：

---

催产素神经元表达对雌性小鼠生长素释放肽的反应。

Ghrelin是一种致雌激素激动剂，直接作用于下丘脑中的神经元，控制食欲和能量平衡。尽管已描述了其在食欲相关神经元中的作用，但尚未完全了解周围生长激素释放肽刺激与脑室旁核中催产素表达之间的关系。我们评估了生长素释放肽在注射生长素释放肽2 h后在卵巢切除的C57BL / 6小鼠中催产素阳性的室旁核神经元中的生长激素释放肽的抑制功能。结果表明，在完好无损的小鼠中，外周促生长素释放肽刺激在发情周期中激活了表达雌激素受体的神经元，并且刺豚鼠相关肽的mRNA表达显着增加。刺痛相关肽神经元轴突与催产素神经元共定位在室旁核中。此外，在催情期，催产素阳性的室旁核神经元对ghrelin的反应受到抑制，而ghrelin则在发情期降低了血清雌二醇的浓度。这些数据表明，生长素释放肽可能通过弓形的刺突相关肽回路抑制催产素阳性神经元的表达，并可能影响雌二醇在鼠发情周期中的作用。揭示生长素释放肽诱导的催产素在下丘脑室旁核中的表达机制，为生长素释放肽相关的食欲研究开阔了视野。这些数据表明，生长素释放肽可能通过弓形的刺突相关肽回路抑制催产素阳性神经元的表达，并可能影响雌二醇在鼠发情周期中的作用。揭示生长素释放肽诱导的催产素在下丘脑室旁核中的表达机制，为生长素释放肽相关的食欲研究开阔了视野。这些数据表明，生长素释放肽可能通过弓形的刺突相关肽回路抑制催产素阳性神经元的表达，并可能影响雌二醇在鼠发情周期中的作用。揭示生长素释放肽诱导的催产素在下丘脑室旁核中的表达机制，为生长素释放肽相关的食欲研究开阔了视野。