Orexins (Oxs) are multifunctional neuropeptides, secreted from the lateral hypothalamus, that stimulate feeding behavior and energy expenditure. In this study, the direct effects of Oxs on the membrane properties of trigeminal motoneurons (TMNs) were examined, which critically participate in the genesis of rhythmical oral motor activities underlying suckling and mastication. Sprague-Dawley rats (3-6 day-old) were used to obtain whole-cell patch-clamp recordings from TMNs. Bath application of Ox-A depolarized the membrane potential and induced inward current, wherein Na⁺ and Ca²⁺ were charge carriers. Transient receptor potential channel activation potentially contributed to current and voltage responses by way of Ox-A. Ox-A increased the peak amplitude and duration at half-amplitude of the medium-duration after hyperpolarization following the action potential. The interspike frequency of steady-state firings during repetitive discharge was increased, along with a shift in the frequency-current relationship occurring toward the left. Extracellular and intracellular Ca²⁺ were involved in regulating modulatory effects, but a requisite level of intracellular Ca²⁺ was not essential for Ox-induced upregulation of the interspike frequency. Ox-A also enhanced conditional bursting induced by N-methyl-d-aspartate and 5-HT, suggesting it participates in modulating TMNs’ discharge patterns during various oral motor activities.

食欲素（Oxs）是下丘脑外侧分泌的多功能神经肽，可刺激进食行为和能量消耗。在这项研究中，研究了Oxs对三叉神经元神经元（TMNs）膜特性的直接影响，它严格参与了哺乳和咀嚼下的节律性口腔运动活动的发生。使用Sprague-Dawley大鼠（3-6天大）从TMN获得全细胞膜片钳记录。在浴中使用Ox-A可使膜电位去极化并感应出内向电流，其中Na ⁺和Ca ²⁺是电荷载体。瞬态受体电位通道激活可能通过Ox-A促进电流和电压响应。Ox-A增加了跟随动作电位的超极化后中等持续时间的半峰的幅度和持续时间。重复放电过程中稳态点火的尖峰频率增加，并且频率-电流关系向左移动。细胞外和细胞内Ca ²⁺参与调节调节作用，但细胞内Ca ²⁺的必需水平对于Ox诱导的间突频率上调不是必需的。Ox-A还增强了N-甲基-d诱导的条件性爆发-天冬氨酸和5-HT，表明它参与了各种口腔运动活动中TMNs放电模式的调节。