Wang Y F, Negoro H, Honda K
Department of Physiology, Fukui Medical School, Japan.
J Neuroendocrinol. 1996 Jun;8(6):427-31. doi: 10.1046/j.1365-2826.1996.04703.x.
Extracellular recordings of the electrical activity of oxytocin neurones were made from the supraoptic nuclei (SON) of lactating rats, and the milk-ejection bursts and the background activity of oxytocin neurones were investigated during unilateral and bilateral suckling. When application of pups was limited to the nipples on either the same side (ipsilateral suckling) or the side opposite (contralateral suckling) to the oxytocin neurone recorded, the burst amplitude and background firing rate were significantly (P < 0.05) lower and the inter-burst interval was significantly (P < 0.05) longer than during bilateral suckling. Furthermore, the burst amplitude was significantly (P < 0.05) lower during ipsilateral suckling than during contralateral suckling. The majority of the oxytocin neurones showed a gradual increase in the burst amplitude during bilateral (88.9%) and contralateral (77.3%) suckling, but during ipsilateral suckling only 40% of the neurones did. The inter-burst interval became shorter with the progress of the milk ejection reflex during any mode of suckling. Three pairs of oxytocin neurones recorded simultaneously from both SON were successfully tested for the effect of bilateral and unilateral suckling on the electrical activity, and the results showed the same direction of change in the burst amplitude, background activity and burst interval as shown in single side recordings. These findings indicate that the burst amplitude mainly depends on the amount of afferent suckling signals arising from the nipples on the side opposite to the recording side, and that there may exist bilateral summation centres coordinating with the synchronization mechanism of milk-ejection bursts of oxytocin neurones.
对泌乳大鼠视上核（SON）中的催产素神经元进行细胞外电活动记录，研究单侧和双侧哺乳期间催产素神经元的射乳爆发和背景活动。当将幼崽的吸吮限制在记录的催产素神经元同侧（同侧哺乳）或对侧（对侧哺乳）的乳头时，与双侧哺乳相比，爆发幅度和背景放电频率显著降低（P<0.05），爆发间隔显著延长（P<0.05）。此外，同侧哺乳时的爆发幅度显著低于对侧哺乳（P<0.05）。大多数催产素神经元在双侧（88.9%）和对侧（77.3%）哺乳期间爆发幅度逐渐增加，但在同侧哺乳期间只有40%的神经元如此。在任何哺乳模式下，随着射乳反射的进行，爆发间隔都会缩短。从双侧视上核同时记录的三对催产素神经元成功测试了双侧和单侧哺乳对电活动的影响，结果显示爆发幅度、背景活动和爆发间隔的变化方向与单侧记录相同。这些发现表明，爆发幅度主要取决于记录侧对侧乳头产生的传入吸吮信号的量，并且可能存在与催产素神经元射乳爆发同步机制相协调的双侧总和中心。
