Sutherland R C, Fink G
Brain Res. 1983 Aug 29;273(2):291-6. doi: 10.1016/0006-8993(83)90853-3.
The neural pathways involved in the milk ejection reflex have been studied with the aid of the 2-deoxyglucose (2DG) method. All the experiments were carried out on Wistar female rats, 9-11 days post-partum, which had been separated from their pups (except for one) overnight. The effect of suckling on the relative metabolic activity (RMA) of the brain was studied in conscious rats and in rats anaesthetized with urethane. Control animals were similarly treated but were not suckled. In addition, the effect of mammary nerve stimulation on RMA was studied in animals anaesthetized with urethane; sham-operated animals served as controls for this group. Suckling (minimum of 10 pups) in conscious animals had no apparent effect on the RMA of any of the brain areas measured. However, in anaesthetized rats, suckling produced a significant increase in the RMA of the paraventricular and supraoptic nuclei (PVN and SON), but had no effect on the RMA of any other brain area or the pituitary gland. Stimulation of the mammary nerve, with a stimulus that causes milk ejection and an increase in prolactin release, produced a significant increase in the RMA of the PVN, SON, the pars distalis and pars nervosa and the spinothalamic tract, and a significant decrease in the ventromedial and mediodorsal nuclei of the thalamus, the zona incerta, the red nucleus and the ventral nucleus of the lateral lemniscus. These results show that suckling significantly increases the metabolic activity of afferent terminals in the PVN and SON. Activation of the cell bodies of the PVN and SON, as assessed by increased RMA of the pituitary gland, could be evoked by the more intense stimulus of mammary nerve stimulation. The ascending pathway from the mammary nerve involves the spinothalamic tract but could not be traced beyond the midbrain. The lack of effect of suckling in conscious animals may have been due to the inhibitory influence of stress mediated by forebrain structures.
借助2-脱氧葡萄糖（2DG）法对参与排乳反射的神经通路进行了研究。所有实验均在产后9 - 11天的Wistar雌性大鼠身上进行，这些大鼠已与幼崽（除一只外）分开过夜。在清醒大鼠和用乌拉坦麻醉的大鼠中研究了哺乳对大脑相对代谢活性（RMA）的影响。对照动物接受同样的处理，但不进行哺乳。此外，在乌拉坦麻醉的动物中研究了乳腺神经刺激对RMA的影响；假手术动物作为该组的对照。清醒动物的哺乳（至少10只幼崽）对所测量的任何脑区的RMA均无明显影响。然而，在麻醉大鼠中，哺乳使室旁核和视上核（PVN和SON）的RMA显著增加，但对其他任何脑区或垂体的RMA均无影响。刺激乳腺神经，该刺激可引起排乳并增加催乳素释放，使PVN、SON、远侧部和神经部以及脊髓丘脑束的RMA显著增加，使丘脑腹内侧核和背内侧核、未定带、红核和外侧丘系腹侧核的RMA显著降低。这些结果表明，哺乳显著增加了PVN和SON中传入终末的代谢活性。通过垂体RMA增加评估的PVN和SON细胞体的激活可由乳腺神经刺激的更强刺激诱发。来自乳腺神经的上行通路涉及脊髓丘脑束，但在中脑以上无法追踪。清醒动物中哺乳无影响可能是由于前脑结构介导的应激抑制作用。
