Role of Vagal nerve in Airway Hyperresponsiveness.

虽然迷走神经在支气管哮喘发病机制中的重要性已被报道，但其确切作用仍不完全清楚。为了进一步阐明这一问题，我们进行了以下实验：首先，我们评估了迷走神经反射在组胺诱导的支气管收缩（HIB）中的可能作用，并确定了组胺对迷走神经的作用部位。为此目的，我们研究了双侧颈迷走神经切断术，六甲双铵（2毫克/公斤）或河豚毒素（0.5毫克/公斤）对HIB（8微克/公斤，静脉注射）在麻醉和机械通气的豚鼠。我们还研究了阿托品（1 mg/kg）是否能降低迷走神经切断后的HIB，包括六烃季铵或河豚毒素的作用，结果表明：1）迷走神经切断、六烃季铵或河豚毒素均能显著增强对组胺的反应。2)普萘洛尔增加HIB和HIB进一步增强迷走神经切断术治疗的动物 ...更多信息 心得安3)阿托品显着抑制HIB后迷走神经切断术，六烃季铵或河豚毒素。这些结果表明，节后迷走神经在HIB中起兴奋作用，通过从神经末梢释放乙酰胆碱。第二，为了阐明局部反射是否能释放速激肽，我们研究了阿托品（10 μ <-6>M）、河豚毒素（TTX）（10 μ <-7>M）对缓激肽诱发的豚鼠离体气管平滑肌（TSM）收缩的影响。阿托品不改变缓激肽在对照动物中引起的收缩。TTX抑制缓激肽诱导的收缩。在辣椒素预处理的动物中，阿托品和TTX均不影响缓激肽引起的TSM收缩，这些结果表明缓激肽可能引起局部神经介导的TSM收缩作用，而不引起传出迷走神经末梢的乙酰胆碱释放，推测是通过轴突反射从迷走神经传出末梢释放速激肽。少

Although the importance of the vagal nerve in the pathogenesis of bronchial asthma has been reported, its precise contribution is still not fully understood. To shed more light on this area, we performed the following experiments.First, we evaluated the possible contribution of vagal reflex in Histamine-Induced Bronchoconstriction (HIB), and decided the site of action of histamine on the vagal nerve. For this purpose, we studied the effects of the bilateral cervical vagotomy, hexamethonium (2 mg/kg) or tetrodotox in (0.5 mg/kg) on HIB (8 mug/kg, iv) in anesthetized and mechanically ventilated guinea pigs. We also studied whether or not atropine (1 mg/kg) decreases HIB after vagotomy, including either the treatment of hexamethonium or tetrodotoxin.The following results were obtained ; 1) The response to histamine was significantly enhanced by the vagotomy, hexamethonium or tetrodotoxin. 2) Propranolol increased HIB and HIB was further enhanced by the vagotomy in the animals treated with … More propranolol. 3) Atropine significantly suppressed HIB after the vagotomy, hexamethonium or tetrodotoxin. These results suggest that the postganglionic vagus nerve plays an excitatory role in HIB through the release of acetylcholine from the nerve terminals. It is also suggested that the vagal reflex mainly exhibits an inhibitory role in the HIB of guinea pigs, presumably by theSecond, to elucidate whether the local reflex may release tachykinin, we studied the effects of atropine (10^<-6> M), tetrodotoxin (TTX) (10^<-7> M) on the bradykinin induced contraction of guinea pig Tracheal Smooth Muscle (TSM) in vitro, with or without capsaicin pretreatment. Atropine did not change the contraction induced by bradykinin in the control animals. TTX suppressed bradykinin-induced contraction. Neither atropine nor TTX did affect bradykinin-induced contraction of TSM in the animals with capsaicin pretreatment.These results indicated that bradykinin may cause a local neurally mediated action in TSM contraction, without release of acetylcholine from efferent vagal nerve terminals, presumably by the release of tachykinins from vagal efferent endings through axon reflex. Less