Lindén A, Löfdahl C G, Ullman A, Skoogh B E
Division of Pulmonary Medicine, University of Göteborg, Sweden.
Eur Respir J. 1993 Mar;6(3):425-33.
In guinea-pig isolated airways, nonadrenergic, noncholinergic (NANC) neural responses converge towards a similar level of smooth muscle tone, via a contraction when the tone is low prior to stimulation, and via a relaxation when the tone is high prior to stimulation. We wanted to assess the effect of simultaneous parasympathetic activation on these converging NANC responses, with and without the addition of sympathetic activation. In guinea-pig isolated airways, the spontaneous airway tone was initially abolished by indomethacin (10 microM). In one series, adrenergic depletion by guanethidine (10 microM) was then established, with and without cholinergic blockade by atropine (1 microM). In another series, either cholinergic blockade by atropine (1 microM) or no blockade was utilized. Responses to electrical field stimulation (1,200 mA, 0.5 ms, 3 Hz for 240 s) were studied with no induced tone, at a moderate (0.3 microM) and at a near-maximum (6 microM), histamine-induced tone. The mean level of the tonus equilibrium (% of maximum tone) was higher with the simultaneous NANC and parasympathetic activation than with NANC activation alone (75% compared with 44%, in the main bronchus, n = 8). The level of the tonus equilibrium was also higher with the simultaneous NANC, sympathetic and parasympathetic activation than with NANC and sympathetic activation only (49% compared with 21%, in the main bronchus, n = 8). The pattern was similar in the distal trachea. In conclusion, NANC neural responses can stabilize smooth muscle tone, and this stabilizing effect can be modulated by both parasympathetic and sympathetic activation, in guinea-pig isolated airways.
在豚鼠离体气道中，非肾上腺素能、非胆碱能（NANC）神经反应通过刺激前张力较低时的收缩以及刺激前张力较高时的舒张，趋向于达到相似的平滑肌张力水平。我们想要评估同时激活副交感神经对这些趋同的NANC反应的影响，以及添加或不添加交感神经激活的情况。在豚鼠离体气道中，先用吲哚美辛（10微摩尔）消除自发性气道张力。在一组实验中，随后使用胍乙啶（10微摩尔）耗竭肾上腺素能，同时使用或不使用阿托品（1微摩尔）进行胆碱能阻滞。在另一组实验中，要么使用阿托品（1微摩尔）进行胆碱能阻滞，要么不进行阻滞。研究了在无诱导张力、中等组胺诱导张力（0.3微摩尔）和接近最大组胺诱导张力（6微摩尔）条件下，对电场刺激（1200毫安，0.5毫秒，3赫兹，持续240秒）的反应。与单独的NANC激活相比，同时激活NANC和副交感神经时，张力平衡的平均水平更高（在主支气管中，分别为75%和44%，n = 8）。与仅激活NANC和交感神经相比，同时激活NANC、交感神经和副交感神经时，张力平衡水平也更高（在主支气管中，分别为49%和21%，n = 8）。在远端气管中，情况类似。总之，在豚鼠离体气道中，NANC神经反应可稳定平滑肌张力，且这种稳定作用可被副交感神经和交感神经激活所调节。
