Izumi H, Karita K
Department of Physiology, Tohoku University School of Dentistry, Sendai, Japan.
J Auton Nerv Syst. 1993 Mar;42(3):215-23. doi: 10.1016/0165-1838(93)90366-3.
In 36 cats under nembutal anaesthesia, stimulation of the central end of the cut vagus nerve caused blood flow to increase in only the ipsilateral side in six cats (17%) and in the bilateral sides in 30 cats (83%) in the lower lips. Pretreatment with hexamethonium to block nicotinic synapses in autonomic ganglia resulted in a time-dependent reduction of the reflex vasodilator response, while phentolamine, propranolol (alpha-, beta-adrenoreceptor antagonists) and tripelennamine (histamine receptor antagonist) had no effect. Pretreatment with atropine (muscarinic receptor antagonist) showed a slight, but not statistically insignificant attenuation of the reflex vasodilatation. Ipsilateral section of either the glossopharyngeal nerve root or the inferior alveolar nerve completely abolished the reflex vasodilator response elicited by central vagal stimulation. The reflex vasodilator response induced by stimulation of the central end of the cut vagus nerve was abolished by topical capsaicin application on the central cut ends of the vagus nerve but not by capsaicin on the inferior alveolar nerve. These results suggest that there is a cutaneous reflex vasodilator system that can be activated via capsaicin-sensitive afferent fibres in the vagus nerve. Parasympathetic vasodilator fibres of this system emerge from the brain stem with the glossopharyngeal nerve and reach the blood vessels in the cat mandibular lip via the inferior alveolar nerve.
在36只戊巴比妥麻醉的猫中，刺激切断的迷走神经中枢端，下唇血流仅在6只猫（17%）的同侧增加，在30只猫（83%）的双侧增加。用六甲铵预处理以阻断自主神经节中的烟碱样突触，导致反射性血管舒张反应随时间依赖性降低，而酚妥拉明、普萘洛尔（α、β肾上腺素受体拮抗剂）和曲吡那敏（组胺受体拮抗剂）则无作用。用阿托品（毒蕈碱受体拮抗剂）预处理，反射性血管舒张有轻微但无统计学意义的减弱。切断舌咽神经根或下牙槽神经的同侧，完全消除了中枢迷走神经刺激引起的反射性血管舒张反应。切断的迷走神经中枢端刺激诱导的反射性血管舒张反应，通过在迷走神经中枢切断端局部应用辣椒素而被消除，但在下牙槽神经应用辣椒素则无此作用。这些结果表明，存在一种皮肤反射性血管舒张系统，可通过迷走神经中对辣椒素敏感的传入纤维激活。该系统的副交感神经血管舒张纤维与舌咽神经一起从脑干发出，通过下牙槽神经到达猫下颌唇的血管。
