Experimental study of chemical transmitter of the swallowing center in the patients with dysphasia

在人工通气、颈迷走交感神经切除的猫上，用α-氯醛糖和乌拉坦深度麻醉，观察电刺激舌神经（LN）中央切断端引起下唇副交感神经反射性血管舒张的中枢机制是否包括三叉神经脊核（VSP）。为此，我们在脑干内进行微量注射，以产生非选择性的、可逆的局部麻醉（利多卡因）或体细胞选择性的、不可逆的神经毒性损伤（红藻氨酸）。通过微量注射利多卡因（2%; 1μl/部位）局部麻醉Vsp，可逆地显著降低同侧LN诱发的副交感神经反射血管舒张。将红藻氨酸（10 mM/部位; 1μl）注入刺激LN同侧的Vsp，可使反射性血管舒张反应不可逆地减弱，但对刺激对侧LN引起的血管舒张反应无影响。这种微量注射红藻氨酸到Vsp没有影响所引起的电刺激同侧下唾液核的血管舒张。电刺激Vsp可引起下唇血流量增加，其强度和频率依赖性与体循环动脉血压升高或降低无关。六烃季铵1.0mg/kg，I.（五）显著降低了电刺激LN或VSP的中央切割端引起的血管舒张反应，每个都达到相似的程度。六烃季铵后，两种血管舒张反应均显示时间依赖性恢复。这些结果表明，VSP是一个重要的延髓中继LN诱发的副交感神经反射血管扩张在猫下唇。

We examined whether the trigerainal spinal nucleus (Vsp) forms part of the central mechanism by which electrical stimulation of the central cut end of the lingual nerve (LN) evokes parasympathetic reflex vasodilatation in the lower lip in artificially ventilated, cervically vagosympathectomized cats deeply anesthetized with α-chloralose and urethane. For this purpose, we made microinjections within the brain stem to produce nonselective, reversible local anesthesia (lidocaine) or soma-selective, irreversible neurotoxic damage (kainic acid). Local anesthesia of Vsp by microinjection of lidocaine (2%; 1μl/site) reversibly and significantly reduced the ipsilateral-LN-evoked parasympathetic reflex vasodilatation. Unilateral microinjection of kainic acid(10mM/site; 1μl) into Vsp ipsilateral to the stimulated LN led to an irreversible reduction in the reflex vasodilatation but had no effect on the vasodilatation elicited by stimulation of the contralateral LN. Such microinjection of kainic acid into Vsp had no effect on the vasodilatation evoked by electrical stimulation of the ipsilateral inferior salivatory nucleus. Electrical stimulation of Vsp elicited a blood flow increase in the lower lip in an intensity- and frequency-dependent manner, regardless of whether systemic arterial blood pressure roseOr fell. Hexamethonium (1.0mg/kg, I. v.) significantly reduced the vasodilator responses elicited by electrical stimulation of the central cut end of LN or Vsp, each to a similar degree. After hexamethonium, both vasodilator responses showed time-dependent recovery. These results strongly suggest that Vsp is an important bulbar relay for LN-evoked parasympathetic reflex vasodilatation in the cat lower lip.