Altiere R J, Szarek J L, Diamond L
J Appl Physiol Respir Environ Exerc Physiol. 1984 Nov;57(5):1536-44. doi: 10.1152/jappl.1984.57.5.1536.
Functional innervation of cat airways smooth muscle was examined in isolated segments of trachea and bronchi using electrical field stimulation (EFS) techniques. Field stimulation caused contraction in tissues at resting tone and biphasic responses (contraction followed by relaxation) in tissues precontracted with 5-hydroxytryptamine (5-HT). Contractions were abolished by 10(-6) M atropine. Inhibitory responses were dependent on impulse voltage, duration, and frequency. At low voltages (less than or equal to 10 V) and pulse durations (less than or equal to 0.3 ms), EFS induced relaxations were abolished by 3 X 10(-6) M tetrodotoxin (TTX). Greater stimulus parameters elicited TTX-resistant relaxations. Pretreatment of the tissues with 10(-6) M propranolol and 10(-5) M guanethidine caused rightward shifts in relaxation frequency-response curves. These findings indicate that cat airways are innervated by excitatory cholinergic, inhibitory adrenergic, and inhibitory nonadrenergic noncholinergic (NANC) nerves. Pretreatment of the tissues with hexamethonium, cimetidine, indomethacin, or nordihydroguaiaretic acid did not affect NANC relaxation responses. It is concluded that NANC inhibitory responses in cat airway smooth muscle are mediated through intrinsic postganglionic nerve fibers and occur independently of histamine H2-receptor activation and without involvement of cyclooxygenase or lipoxygenase products of arachidonic acid metabolism.
利用电场刺激（EFS）技术，在猫气管和支气管的离体节段中研究了气道平滑肌的功能性神经支配。电场刺激使处于静息张力的组织发生收缩，并使预先用5-羟色胺（5-HT）预收缩的组织产生双相反应（收缩后松弛）。10⁻⁶M阿托品可消除收缩。抑制性反应取决于脉冲电压、持续时间和频率。在低电压（小于或等于10V）和脉冲持续时间（小于或等于0.3ms）时，EFS诱导的松弛被3×10⁻⁶M河豚毒素（TTX）消除。更大的刺激参数引发了对TTX耐药的松弛。用10⁻⁶M普萘洛尔和10⁻⁵M胍乙啶预处理组织会使松弛频率-反应曲线向右移动。这些发现表明，猫气道受兴奋性胆碱能、抑制性肾上腺素能和抑制性非肾上腺素能非胆碱能（NANC）神经支配。用六甲铵、西咪替丁、吲哚美辛或去甲二氢愈创木酸预处理组织不会影响NANC松弛反应。得出的结论是，猫气道平滑肌中的NANC抑制性反应是通过内在的节后神经纤维介导的，并且独立于组胺H2受体激活而发生，且不涉及花生四烯酸代谢的环氧化酶或脂氧化酶产物。
