Pomrenze Matthew B, Millan E Zayra, Hopf F Woodward, Keiflin Ronald, Maiya Rajani, Blasio Angelo, Dadgar Jahan, Kharazia Viktor, De Guglielmo Giordano, Crawford Elena, Janak Patricia H, George Olivier, Rice Kenner C, Messing Robert O
Division of Pharmacology and Toxicology, College of Pharmacy, The University of Texas at Austin Austin, TX, USA.
Department of Neurology, University of California, San Francisco San Francisco, CA, USA.
Front Neurosci. 2015 Dec 24;9:487. doi: 10.3389/fnins.2015.00487. eCollection 2015.
Corticotrophin-releasing factor (CRF) is a 41 amino acid neuropeptide that coordinates adaptive responses to stress. CRF projections from neurons in the central nucleus of the amygdala (CeA) to the brainstem are of particular interest for their role in motivated behavior. To directly examine the anatomy and function of CRF neurons, we generated a BAC transgenic Crh-Cre rat in which bacterial Cre recombinase is expressed from the Crh promoter. Using Cre-dependent reporters, we found that Cre expressing neurons in these rats are immunoreactive for CRF and are clustered in the lateral CeA (CeL) and the oval nucleus of the BNST. We detected major projections from CeA CRF neurons to parabrachial nuclei and the locus coeruleus, dorsal and ventral BNST, and more minor projections to lateral portions of the substantia nigra, ventral tegmental area, and lateral hypothalamus. Optogenetic stimulation of CeA CRF neurons evoked GABA-ergic responses in 11% of non-CRF neurons in the medial CeA (CeM) and 44% of non-CRF neurons in the CeL. Chemogenetic stimulation of CeA CRF neurons induced Fos in a similar proportion of non-CRF CeM neurons but a smaller proportion of non-CRF CeL neurons. The CRF1 receptor antagonist R121919 reduced this Fos induction by two-thirds in these regions. These results indicate that CeL CRF neurons provide both local inhibitory GABA and excitatory CRF signals to other CeA neurons, and demonstrate the value of the Crh-Cre rat as a tool for studying circuit function and physiology of CRF neurons.
促肾上腺皮质激素释放因子（CRF）是一种由41个氨基酸组成的神经肽，可协调机体对应激的适应性反应。杏仁核中央核（CeA）神经元向脑干的CRF投射因其在动机行为中的作用而备受关注。为了直接研究CRF神经元的解剖结构和功能，我们构建了一种BAC转基因Crh-Cre大鼠，其中细菌Cre重组酶由Crh启动子表达。利用Cre依赖的报告基因，我们发现这些大鼠中表达Cre的神经元对CRF具有免疫反应性，并聚集在CeA外侧（CeL）和终纹床核椭圆形核中。我们检测到CeA CRF神经元向臂旁核、蓝斑、背侧和腹侧终纹床核有主要投射，向黑质外侧部、腹侧被盖区和下丘脑外侧有较小的投射。对CeA CRF神经元进行光遗传学刺激，在内侧CeA（CeM）的11%非CRF神经元和CeL的44%非CRF神经元中诱发了GABA能反应。对CeA CRF神经元进行化学遗传学刺激，在相似比例的非CRF CeM神经元中诱导了Fos，但在非CRF CeL神经元中的比例较小。CRF1受体拮抗剂R121919使这些区域的Fos诱导减少了三分之二。这些结果表明，CeL CRF神经元向其他CeA神经元提供局部抑制性GABA和兴奋性CRF信号，并证明了Crh-Cre大鼠作为研究CRF神经元回路功能和生理学工具的价值。
