Is a trigeminal nociception-induced cardiovascular response related to the trigemino-vagal reflex?

研究了电刺激下肺泡神经（IAN）和髓质对猫动脉血压（ABP）的影响。将含有苯基乙醇胺- n -甲基转移酶的WGA HRP注入胸椎脊髓单侧中侧质逆行标记神经元，电刺激后内侧髓质、心房下核（IFT）和吻侧腹侧髓质（RVLM），可诱导显著的血管加压反应。IFT的血管加压反应总是模仿IAN的血管加压反应。刺激三叉神经内插核、三叉神经脊髓束和旁正中网状核的尾侧腹外侧髓质诱导血管降压反应。然而，这些血管降压药反应与TDR时的血管降压药反应不同，可能几乎是迷走神经诱导的心血管反应。只有脊髓化和RVLM损伤电刺激后，基底ABP下降，TDR完全消失。在髓质中，使用免疫组织化学技术绘制了可能的抑制性突触配体的分布。结果表明，去甲肾上腺素能神经元、甘氨酸能神经元、甘氨酸能神经元以及肾上腺素α2A受体、GABAA、GABAB和甘氨酸受体神经元也沿交感反射通路分布，包括RVLM和IFT等。这些结果表明，TDR可能是交感神经系统的负反馈反应，在基础ABP和HR高时容易受到三叉神经区域的有害刺激，并通过三叉神经核和网状结构抑制血管兴奋中枢、RVLM诱导。

We studied effects of electrical stimulation of the inferior alveolar nerve (IAN) and medulla on arterial blood pressure (ABP) in cats. Electrical stimulation of dorsomedial medulla, infratrigeminal nucleus (IFT) and the rostral ventrolateral medulla (RVLM) which has neurons labeled retrogradely by injection of WGA HRP into the unilateral substantia intermedia lateralis of the thoracical spinal cord and containing phenylethanolamine-N-methyl transferaseinduced significant vasopressor response. Vasopressor response on IFT always mimics vasopressor response on IAN. Vasodepressor responses induced when the caudal ventrolateral medulla just ventral to ambiguus nucleus, lateral tegmental field, the trigeminal nucleus interpolaris, trigeminal spinai tract and paramedian reticular nucleus were stimulated. However these vasodepressor responses did not similar to vasodepressor response on TDR and could be almost vagal induced cardio-vascular response. Only after spinalization and electrical stimulation of RVLM lesion, basal ABP decreased and TDR completely disappeared. In medulla, the distribution of possible inhibitory synaptic ligands was mapped using immunohistochemical techniques. It demonstrated that noradrenergic, glycinergic and GABAergic neurons and neurons for adrenaliine α2A receptor, GABAA, GABAB and glycine receptors were also distributed along the sympatho-reflexive route including RVLM and IFT etc. These results suggest that TDR may be negative feedback response to sympathetic nervous system, readily induced by noxious stimulation in the trigeminal region whenever basal ABP and HR are high and that TDR is induced by inhibiting vasoexciting centrer, RVLM through trigeminal nucleus and reticular formation.