Yip P, Palombini B, Coburn R F
J Appl Physiol Respir Environ Exerc Physiol. 1981 Feb;50(2):374-82. doi: 10.1152/jappl.1981.50.2.374.
The inhibitory innervation of the cervical trachea was studied in situ in anesthetized male guinea pigs. We measured effects of electrical stimulation of vagal motor and sympathetic trunk nerve fibers, during atropine, on trachealis muscle tension. Effects of direct transmural stimulation of trachealis muscle were also determined. We confirmed the dual nature of the inhibitory innervation to this muscle. Vagal motor inhibitory nerves are shown to be preganglionic. Neural transmission at the level of the ganglia is characterized by filtering of high frequency action potentials. The neurotransmitter at the myoneural junction is unidentified but is not norepinephrine. Maximal relaxation accounts for about 20-40% of maximal relaxations seen with transmural stimulation of trachealis muscle in the presence of atropine. Sympathetic trunk nerve fibers are also preganglionic. Neurotransmission at the level of the ganglia is apparently 1:1 at high-action potential frequencies. Norepinephrine released presynaptically has access to smooth muscle beta- but not alpha-receptors. Maximal adrenergic relaxations account for 60-80% of total transmural stimulation relaxations. Transmural stimulation relaxations appear to be accounted for by release of neurotransmitter from sympathetic adrenergic plus vagal nonadrenergic postganglionic nerve fibers.
在麻醉的雄性豚鼠体内原位研究了颈段气管的抑制性神经支配。我们测量了在阿托品存在的情况下，电刺激迷走运动神经和交感干神经纤维对气管肌张力的影响。还确定了直接经壁刺激气管肌的效果。我们证实了该肌肉抑制性神经支配的双重性质。迷走运动抑制神经为节前神经。神经节水平的神经传递以高频动作电位的过滤为特征。肌神经接头处的神经递质尚未确定，但不是去甲肾上腺素。最大松弛约占在阿托品存在下经壁刺激气管肌所见最大松弛的20 - 40%。交感干神经纤维也是节前神经。在高动作电位频率下，神经节水平的神经传递显然是1:1。突触前释放的去甲肾上腺素作用于平滑肌β受体而非α受体。最大肾上腺素能松弛占经壁刺激总松弛的60 - 80%。经壁刺激松弛似乎是由交感肾上腺素能节后神经纤维和迷走非肾上腺素能节后神经纤维释放神经递质所致。
