Alguacil L F, Lopez-Ruiz M P, Prieto J C, Alamo C, Cuenca E
Departamento de Fisiología y Farmacología, Universidad de Alcalá de Henares, Madrid, Spain.
Biosci Rep. 1990 Feb;10(1):113-9. doi: 10.1007/BF01116859.
Neither acute nor prolonged exposure to morphine altered cAMP content or spontaneous movements of longitudinal muscle-myenteric plexus strips of the guinea-pig ileum. By contrast, exogenous acetylcholine or electrical stimulation of the strips elicited both a decrease of cAMP concentration and a twitch response. Atropine blocked the effects of stimulation on these parameters. Addition of morphine to electrically stimulated strips inhibited the twitch response but did not affect cAMP levels. Incubation with morphine led to the development of tolerance to the inhibitory effect on twitch activity and prevented the fall in cAMP normally elicited by electrical stimulation. These results suggest that muscarinic activation is associated with a reduction of cAMP content, an effect which would be impaired in opiate-tolerant tissues.
急性或长期暴露于吗啡均不会改变豚鼠回肠纵行肌-肌间神经丛条带的环磷酸腺苷（cAMP）含量或自发运动。相比之下，外源性乙酰胆碱或对条带进行电刺激会引起cAMP浓度降低和抽搐反应。阿托品可阻断刺激对这些参数的影响。向电刺激的条带中添加吗啡可抑制抽搐反应，但不影响cAMP水平。与吗啡共同孵育会导致对抽搐活动抑制作用的耐受性形成，并阻止电刺激正常引起的cAMP下降。这些结果表明，毒蕈碱激活与cAMP含量降低有关，而在阿片耐受组织中这种作用会受到损害。
