Integrate Analysis of Blood Pressure Regulation System in CNS.

血压的颈动脉窦反射通过主动脉弓内的降压神经的压力感受性神经末梢传递到孤束核(NTS)。然而，不仅ADN投射的NTS神经元的突触传递的详细机制以及血管运动反射的调节机制还不清楚。在本研究中，从ADN投射的NTS神经元在向分离的ADN注射Di-1 3-5天后被发现。来自结节神经节的ADN轴突进入脑干形成孤束(ST)，并终止NTS内侧神经元的胞体和树突，释放谷氨酸。内侧NTS神经元对红藻氨酸的敏感性是ADN非投射神经元的2倍。ST诱发的单突触谷氨酸能反应是由非NMDA谷氨酸受体介导的。此外，VR-1(香草素)受体激动剂辣椒素和嘌呤能P2X3受体激动剂a，b-MET都使分离的NTS内侧神经元的谷氨酸释放增加30倍，这表明血管扩张是在脑干水平上操纵的辣椒素和ATP。由于NTS暴露在开放的血脑屏障中，这种功能性的VR-1和嘌呤能调节可能在任何全身治疗中发挥重要作用。

The carotid sinus reflex of the blood pressure is transmitted to the nucleus of the solitary tract (NTS) via baroreceptor nerve terminals in the aortic depressor nerve (ADN) which is located in the aortic arch. However, not only the detailed mechanisms on synapse transmission in the NTS neurons projected from ADN but also modulations of vasomotor reflex have not been clarified.In the present studies, the NTS neurons projected from ADN were identified 3-5 days after injection of Di-1 to the separated ADN.This ADN axon from nodose ganglion entered the brainstem to form the solitary tract (ST) and terminated the soma and dendrites of medial NTS neurons, which released glutamate. The identified medial NTS neurons were sensitive to kainate application by 2-fold relative to the non-projected neurons from ADN.ST evoked mono-synaptic glutamatergic responses were mediated by non-NMDA glutamate receptors in the medial NTS neurons. Furthermore, both capsaicin, a VR-1 (vanilloid) receptors agonist and a, b met ATP, a purinergic P2X3 receptors agonist, increased glutamate release 30-fold relative to the control value in dissociated medial NTS neurons, Which is suggested that vasodilation is manipulated capsaicin and ATP at brainstem level.This functional VR-1 and purinergic regulation might play an important role for any systemic therapies since NTS is exposed to an open blood brain barrier.