Lincoln D W, Hentzen K, Hin T, van der Schoot P, Clarke G, Summerlee A J
Exp Brain Res. 1980 Jan;38(2):151-62. doi: 10.1007/BF00236736.
Electroencephalographic activity (EEG) was recorded from the frontal cortex of unanaesthetized and urethane-anaesthetized lactating rats and analysed in relation to the pattern of milk ejection evoked by the nursing pups. The EEG of the anaesthetized rat fluctuated without experimental intervention between three distinctive patterns defined as synchronized, desychronized, and stage III activity, whilst reflex milk ejection recurred at intervals of about 6 min (range 2- greater than 20 min) throughout the 1-4 h period the pups were left attached to the nipples. For greater than 10 s before and for up to 60 s after each milk ejection, as judged from recordings of intramammary pressure and pup behaviour, the EEG was invariably synchronized throughout. Conversely, milk ejection (n greater than 300) was never observed during long periods of desynchronized, or stage III EEG activity. The vigorous increase in the sucking of the pups at milk ejection failed to produce a desynchronization (arousal) of the EEG as observed with other forms of sensory stimulation. Indeed, the sucking of the pups appeared to produce a soporific change i, the maternal EEG for spontaneous periods of desynchronization were not observed in the 30-60 min following the initial attachment of the pups to the nipples. Similar EEG patterns were seen in the unanaesthetized rat, though arousal from the synchronized state was more easily produced, e.g., by weak auditory signals. Milk ejection, as judged from the behaviour of the pups, recurred at intervals of 2 min or more during each 20-80 min period of nursing. The rat appeared somnolent for most of the nursing period and the EEG was always synchronized for greater than 10 s before each milk ejection (n greater than 200), though her eyes usually remained open. Arousal and desynchronization of the EEG was invariably observed in association with the increased pup behaviour at milk ejection. From these observations and the knowledge that oxytocin release from the neurohypophysis occurs about 10 s before milk ejection, we conclude that a synchronized EEG pattite for the expression of the milk-ejection reflex in the rat.
记录未麻醉和氨基甲酸乙酯麻醉的泌乳大鼠额叶皮质的脑电图活动（EEG），并分析其与哺乳幼崽诱发的喷乳模式的关系。在没有实验干预的情况下，麻醉大鼠的脑电图在三种不同模式之间波动，这三种模式被定义为同步、去同步和Ⅲ期活动，而在幼崽附着在乳头的1-4小时期间，反射性喷乳每隔约6分钟（范围为2-大于20分钟）重复出现。根据乳腺内压力和幼崽行为的记录判断，在每次喷乳前大于10秒和喷乳后长达60秒的时间内，脑电图始终是同步的。相反，在长时间的去同步或Ⅲ期脑电图活动期间从未观察到喷乳（n大于300）。幼崽在喷乳时吸吮力的剧烈增加并未像其他形式的感觉刺激那样引起脑电图的去同步（唤醒）。事实上，幼崽的吸吮似乎产生了一种催眠变化，在幼崽最初附着在乳头后的30-60分钟内未观察到自发去同步期的母体脑电图。未麻醉的大鼠也观察到类似的脑电图模式，尽管从同步状态唤醒更容易产生，例如通过微弱的听觉信号。根据幼崽的行为判断，在每次20-80分钟的哺乳期间，喷乳每隔2分钟或更长时间重复出现。在大多数哺乳期间，大鼠似乎嗜睡，并且在每次喷乳前大于10秒脑电图总是同步的（n大于200），尽管她的眼睛通常保持睁开。在喷乳时幼崽行为增加的同时，总是观察到脑电图的唤醒和去同步。根据这些观察结果以及已知神经垂体释放催产素发生在喷乳前约10秒，我们得出结论，大鼠喷乳反射的表达存在同步脑电图模式。
