McClung R E, Burks T F, Dafny N
Arch Int Pharmacodyn Ther. 1977 Sep;229(1):144-56.
Sensory evoked responses were recorded simultaneously from five structures (caudate nucleus, septum, periaqueductal gray, parafascicular nucleus and reticular formation) reported to play roles in morphine's acute actions (analgesia, dyskinesia) and in the development of tolerance. Daily recordings were made from unanesthetized male Holtzman rats before and after a challenge dose of 10 mg/kg of morphine sulfate over a four day period while tolerance was induced by multiple daily injections of morphine. Three patterns of changes were observed in the individual components of the evoked responses. 1) The challenge dose caused an initial increase in the amplitudes of the P2 and N2 components of the response in the naive rats. This effect was attenuated with each day of drug administration until day four, when the challenge dose was observed to exert no effect. This pattern occurred in the parafascicular nucleus and the septum. 2) Initial increase in P2 and N2 components by morphine was augmented for 2-3 days, after which there was a sharp drop to control values by day four. This pattern was observed in the caudate nucleus and the periaqueductal gray region. 3) Morphine caused a mixture of increases and null effects in the components over the four days. This effect was observed in the reticular formation.
在五个据报道在吗啡的急性作用（镇痛、运动障碍）及耐受性形成中起作用的结构（尾状核、隔区、导水管周围灰质、束旁核和网状结构）上同时记录感觉诱发电位。在4天的时间里，对未麻醉的雄性霍尔兹曼大鼠每日进行记录，记录在给予10mg/kg硫酸吗啡激发剂量之前和之后的情况，同时通过每日多次注射吗啡诱导耐受性。在诱发电位的各个成分中观察到三种变化模式。1）激发剂量使未用药大鼠的反应中P2和N2成分的振幅最初增加。随着给药天数的增加，这种效应逐渐减弱，直到第4天，此时观察到激发剂量没有作用。这种模式出现在束旁核和隔区。2）吗啡引起的P2和N2成分的最初增加在2 - 3天内增强，之后到第4天急剧降至对照值。这种模式在尾状核和导水管周围灰质区域观察到。3）吗啡在4天内对各成分产生增加和无作用的混合效应。这种效应在网状结构中观察到。
