Study on the involvement of primary afferent neurons in microcirculatory dynamics in oral region

本研究用激光多普勒血流仪测量大鼠后爪和嘴唇的血流量，探讨初级传入神经元在微循环血流动力学中的作用。此外，还测量了P物质(SP)从后爪向皮下灌流液中的释放量。电刺激含感觉传入纤维的坐骨神经和隐神经(10V，2 Hz，1ms)30s，可使SP释放增加，并伴有血浆外渗和皮肤血流量增加。用脑组织天蓝渗出法测定血浆渗出量。电刺激精神神经、感觉神经供应嘴唇30秒(5V-20V，2赫兹，1毫秒)，也可增加嘴唇血流量。预先给予辣椒素或Spantide I.A.可显著抑制皮肤和嘴唇血流量的增加。注射酚妥拉明、心得安、阿托品、甲基丝氨酸甲酯或皮下注射美拉明+西咪替丁对另一只手无影响。这些结果提示，小径传入纤维可能通过SP的外周释放在微循环血流动力学的调节中发挥重要作用。

This study was designed to investigate the involvement of primary afferent neurons in microcirculatory hemodynamics by measuring the blood flow of the rat hind paw and lip with a laser Doppler flowmeter. Moreover the amount of substance P (SP) released into subcutaneous perfusates from hind paw was measured. Electrical stimulation of the sciatic and saphenous nerves containing sensory afferent fibers in the hind paw (10V, 2Hz, 1msec duration) for 30sec inauced an increase of SP release with plasma extravasation and an increase of cutaneous blood flow. Plasma extravasation was determined by pontamine sky blue exudation. Electrical stimulation of the mental nerve, sensory nerve supplying lip, (5v-20V, 2Hz, lmsec duration) for 30 sec also led to an increase of lip blood flow. The cutaneous and lip blood flow increases were significantly inhibited by pretreatment with capsaicin or spantide I.a. injection of phentolamine, propranolol, atropine, methysergide or s.c injection of mepyramine plus cimetidine, on the other handy had no effect. These results suggest that through the peripheral release of SP the small-diameter afferent fibers may play an important role in the regulation of microcirculatory hemodynamics.