Tonini M, Onori L, Perucca E, Manzo L, De Ponti F, Crema A
Eur J Pharmacol. 1985 Sep 24;115(2-3):317-20. doi: 10.1016/0014-2999(85)90708-3.
The mechanical responses to morphine were examined in isolated preparations of longitudinal and circular muscle of the guinea-pig colon. In the longitudinal coat, morphine induced a relaxation which was prevented by naloxone, hyoscine and tetrodotoxin. Conversely, in the circular coat morphine caused a contraction which was antagonized by naloxone, mimicked by tetrodotoxin and left unaltered by hyoscine, chlorpheniramine and methysergide. In both muscular layers, morphine depressed (and tetrodotoxin abolished) the non-adrenergic relaxation induced by field stimulation. The action of morphine in the two preparations can thus be explained in terms of inhibition of the tonic excitatory cholinergic or inhibitory non-adrenergic neural control prevailing in the longitudinal and circular muscle respectively.
在豚鼠结肠纵肌和环肌的离体标本中研究了对吗啡的机械反应。在纵肌层，吗啡引起松弛，这种松弛可被纳洛酮、东莨菪碱和河豚毒素所阻断。相反，在环肌层，吗啡引起收缩，这种收缩被纳洛酮拮抗，被河豚毒素模拟，而东莨菪碱、氯苯那敏和甲基麦角新碱对其无影响。在两层肌肉中，吗啡均抑制（河豚毒素可消除）由场刺激诱导的非肾上腺素能松弛。因此，吗啡在这两种标本中的作用可以分别用抑制纵肌中占主导的紧张性兴奋性胆碱能神经控制或环肌中占主导的抑制性非肾上腺素能神经控制来解释。
