Direct projections from hypothalamic orexin neurons to brainstem cardiac vagal neurons.
Direct projections from hypothalamic orexin neurons to brainstem cardiac vagal neurons.
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从下丘脑食欲素神经元到脑干心脏迷走神经元的直接投射。
DOI：
10.1016/j.neuroscience.2016.09.038
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发表时间：
2016-12-17
期刊：
影响因子：
3.3
通讯作者：
Mendelowitz D
中科院分区：
文献类型：
--
作者：
Dergacheva O;Yamanaka A;Schwartz AR;Polotsky VY;Mendelowitz D
众所周知，增食欲素神经元可以增强交感神经对心血管功能的控制，但增食欲素神经元在副交感神经心脏调节中的作用尚不清楚。为了验证食欲素神经元参与副交感神经控制的假说，我们选择性地在食欲素-Cre转基因大鼠的食欲素神经元中表达了通道视紫红质-2(ChR2)，并检测了迷走神经背侧运动核(DMV)的心脏迷走神经(CVN)的突触后电流。同时光刺激和记录在下丘脑外侧区表达ChR2的增食欲素神经元，导致可靠的动作电位激发和大的全细胞电流，这表明ChR2的强表达和可靠的光发生兴奋。光刺激DMV内表达ChR2的纤维在44个CVN中有16个产生了短潜伏期(3.2~8.5ms)的突触后电流。这些反应是不同的，包括兴奋性谷氨酸(63%)和抑制性GABA能(37%)突触后电流。本研究结果提示，不同的增食欲素神经元亚群可能对脑干CVN产生不同的影响，因此可能在心脏的副交感神经控制中发挥不同的功能作用。
Orexin neurons are known to augment the sympathetic control of cardiovascular function, however the role of orexin neurons in parasympathetic cardiac regulation remains unclear. To test the hypothesis that orexin neurons contribute to parasympathetic control we selectively expressed channelrhodopsin-2 (ChR2) in orexin neurons in orexin-Cre transgenic rats and examined postsynaptic currents in cardiac vagal neurons (CVNs) in the dorsal motor nucleus of the vagus (DMV). Simultaneous photostimulation and recording in ChR2-expressing orexin neurons in the lateral hypothalamus resulted in reliable action potential firing as well as large whole-cell currents suggesting a strong expression of ChR2 and reliable optogenetic excitation. Photostimulation of ChR2-expressing fibers in the DMV elicited short-latency (ranging from 3.2 ms to 8.5 ms) postsynaptic currents in 16 out of 44 CVNs tested. These responses were heterogeneous and included excitatory glutamatergic (63%) and inhibitory GABAergic (37%) postsynaptic currents. The results from this study suggest different sub-population of orexin neurons may exert diverse influences on brainstem CVNs and therefore may play distinct functional roles in parasympathetic control of the heart.