Yang B, Schlosser R J, McCaffrey T V
Department of Otorhinolaryngology, Mayo Clinic, Rochester, Minnesota 55905, USA.
Ann Otol Rhinol Laryngol. 1997 Mar;106(3):230-6. doi: 10.1177/000348949710600309.
The release of endogenous neurotransmitters plays an important role in the airway mucosal defense system. We studied the in vitro effect of methacholine, a beta-methyl ester of acetylcholine, on the ciliary beat frequency (CBF) of human adenoid explants and its mechanism of action. Tissue explants were cultured at 35 degrees C and covered with 1.0 mL of culture medium: minimum essential Eagle's medium (MEM) containing L-arginine (1.2 x 10(-3) mol/L). Methacholine was added to the cultured tissue at concentrations of 10(-10), 10(-8), and 10(-6) mol/L. The CBF was determined by phase contrast microscopy and microphotometry. Methacholine increased CBF in a dose-dependent manner with a maximum increase of 23.0% +/- 1.8% (p < .001). Atropine (10(-6) mol/L) significantly inhibited the ciliostimulatory effects of methacholine (p < .0007). The role of endogenous prostaglandins in methacholine-induced ciliostimulation was determined by treating specimens with a cyclooxygenase inhibitor (diclofenac sodium). Diclofenac (10(-6) mol/L) significantly inhibited the ciliostimulatory effects of methacholine (p < .0007). To determine if nitric oxide (NO) acts as an intermediary in ciliostimulation by methacholine, endogenous NO production was inhibited by treating specimens with an L-arginine analog, NG-nitro-L-arginine methyl ester (L-NAME), prior to addition of methacholine. L-NAME (10(-6) mol/L) inhibited the effects of methacholine in L-arginine-free MEM (p < .008), and this inhibition was reversed by L-arginine (10(-3) mol/L). To further examine the actions of NO in methacholine-induced ciliostimulation, a cyclic guanosine 3'5'-monophosphate (cGMP) kinase inhibitor (KT-5823) was used, prior to the addition of methacholine. KT-5823 (10(-6) mol/L) significantly inhibited the effects of methacholine (p < .0001). Ciliostimulation by methacholine in human upper airway mucosa involves both prostaglandin and NO second messengers and activation of a cGMP-dependent kinase.
内源性神经递质的释放在气道黏膜防御系统中发挥着重要作用。我们研究了乙酰胆碱的β-甲酯——乙酰甲胆碱对人腺样体组织块纤毛摆动频率（CBF）的体外作用及其作用机制。组织块在35℃培养，覆盖1.0 mL培养基：含L-精氨酸（1.2×10⁻³mol/L）的最低必需 Eagle 培养基（MEM）。将乙酰甲胆碱以10⁻¹⁰、10⁻⁸和10⁻⁶mol/L的浓度加入培养的组织中。通过相差显微镜和显微光度测定法测定CBF。乙酰甲胆碱以剂量依赖性方式增加CBF，最大增加23.0%±1.8%（p <.001）。阿托品（10⁻⁶mol/L）显著抑制乙酰甲胆碱的纤毛刺激作用（p <.0007）。通过用环氧化酶抑制剂（双氯芬酸钠）处理标本，确定内源性前列腺素在乙酰甲胆碱诱导的纤毛刺激中的作用。双氯芬酸（10⁻⁶mol/L）显著抑制乙酰甲胆碱的纤毛刺激作用（p <.0007）。为了确定一氧化氮（NO）是否在乙酰甲胆碱诱导的纤毛刺激中作为中介起作用，在加入乙酰甲胆碱之前，用L-精氨酸类似物NG-硝基-L-精氨酸甲酯（L-NAME）处理标本以抑制内源性NO的产生。L-NAME（10⁻⁶mol/L）在无L-精氨酸的MEM中抑制乙酰甲胆碱的作用（p <.008），并且这种抑制作用被L-精氨酸（10⁻³mol/L）逆转。为了进一步研究NO在乙酰甲胆碱诱导的纤毛刺激中的作用，在加入乙酰甲胆碱之前使用环磷酸鸟苷（cGMP）激酶抑制剂（KT-5823）。KT-5823（10⁻⁶mol/L）显著抑制乙酰甲胆碱的作用（p <.0001）。乙酰甲胆碱对人上呼吸道黏膜的纤毛刺激涉及前列腺素和NO两种第二信使以及cGMP依赖性激酶的激活。
