Institute of Anatomy, University of Rostock, P. O. Box 100888, 18055, Rostock, Germany.
Brain Struct Funct. 2012 Apr;217(2):233-56. doi: 10.1007/s00429-011-0343-8. Epub 2011 Sep 21.
The orexinergic system interacts with several functional states of emotions, stress, hunger, wakefulness and behavioral arousal through four pathways originating in the lateral hypothalamus (LH). Hundreds of orexinergic efferents have been described by tracing studies and direct immunohistochemistry of orexin in the forebrain, olfactory regions, hippocampus, amygdala, septum, basal ganglia, thalamus, hypothalamus, brain stem and spinal cord. Most of these tracing studies investigated the whole orexinergic projection to all regions of the intracranial part of the CNS. To identify the orexinergic efferents at the subnuclear level of resolution, we focussed on the orexinergic target in the amygdala, which is substantially involved in the LH output and contributes mostly to the functional outcome of the orexinergic system and the basal ganglia. Immunohistochemical identification of axonal orexin A and orexin B in male adult rats has been performed on serial sections. In the extended amygdala many new orexinergic targets were found in the anterior amygdaloid area (dense), anterior cortical nucleus (moderate), amygdalostriatal transition region (moderate), basolateral regions (moderate), basomedial nucleus (moderate), several bed nucleus of the stria terminals regions (few to dense), central amygdaloid subdivisions (dense), posteromedial cortical nucleus (moderate) and medial amygdaloid subnuclei (dense). Furthermore, the entopeduncular nucleus has been newly identified as another target for orexinergic fibers with a high density. These results suggest that subdivisions and subnuclei of the extended amygdala are specific targets of the orexinergic system.
食欲肽能系统通过起源于外侧下丘脑 (LH) 的四条途径与情绪、应激、饥饿、觉醒和行为唤醒的几种功能状态相互作用。通过示踪研究和对前脑、嗅觉区域、海马体、杏仁核、隔区、基底神经节、丘脑、下丘脑、脑干和脊髓中的食欲肽进行直接免疫组织化学研究，已经描述了数百个食欲肽能传出纤维。这些示踪研究中的大多数都研究了整个食欲肽能投射到颅内中枢神经系统的所有区域。为了在亚核水平上确定食欲肽能传出纤维，我们专注于杏仁核中的食欲肽能靶标，该靶标在 LH 输出中起着重要作用，并对食欲肽能系统和基底神经节的功能结果做出了最大贡献。已经对雄性成年大鼠的连续切片进行了免疫组织化学鉴定，以确定轴突食欲肽 A 和食欲肽 B。在扩展的杏仁核中，在前杏仁核区（密集）、前皮质核（中度）、杏仁核纹状体过渡区（中度）、基底外侧区（中度）、基底内侧核（中度）、几个终纹床核区（稀疏至密集）、中央杏仁核亚区（密集）、后皮质核（中度）和内侧杏仁核亚核（密集）中发现了许多新的食欲肽能靶标。此外，现已确定苍白球为另一个具有高密度食欲肽能纤维的靶标。这些结果表明，扩展杏仁核的亚区和亚核是食欲肽能系统的特定靶标。
