Neumann I, Porter D W, Landgraf R, Pittman Q J
Neuroscience Research Group, University of Calgary, Alberta, Canada.
Am J Physiol. 1994 Sep;267(3 Pt 2):R852-8. doi: 10.1152/ajpregu.1994.267.3.R852.
Suckling in the lactating rat (days 6-10 of lactation) was used to characterize the effects of intracerebral oxytocin (Oxt) antisense oligonucleotide treatment on the hypothalamo-neurohypophysial system. Vehicle, mixed bases, Oxt antisense, or vasopressin antisense oligonucleotides (2.5 micrograms/0.5 microliter each) were infused directly into the left and right supraoptic nucleus (SON), 4 h before a litter of 10 pups was allowed to suckle for 30 min. In the Oxt antisense group, there was a significant reduction in the number of milk ejection reflexes (to 34.6 +/- 4.88%, P < 0.001), as well as in the weight gain of the litter (to 18.8 +/- 6.98%, P < 0.03) compared with vehicle (100%)-, mixed base-, or vasopressin antisense-treated animals, which did not differ from each other. The time to onset of suckling, however, was unchanged. Compared with presuckling values, plasma Oxt was significantly increased in all four groups 30 min after onset of suckling (vehicle, to 325 +/- 117%; mixed bases, to 258 +/- 48.2%; vasopressin antisense, to 330 +/- 55.7%), but this increase was less pronounced in Oxt antisense-treated rats (to 157 +/- 20.5%; P < 0.05 vs. vasopressin antisense). In contrast to these changes in neuroendocrine functions during suckling, Oxt as well as vasopressin content and Oxt immunoreactivity in posterior pituitaries and the SON, respectively, did not differ among groups. Our data indicate rapid and specific effects of an Oxt antisense oligonucleotide infused into the SON on neuroendocrine, suckling-related parameters that are not due to depleted stores of Oxt in the hypothalamo-neurohypophysial system.
采用哺乳期大鼠（泌乳第6 - 10天）来研究脑室内注射催产素（Oxt）反义寡核苷酸对下丘脑 - 神经垂体系统的影响。在一窝10只幼崽哺乳30分钟前4小时，将溶剂、混合碱基、Oxt反义或加压素反义寡核苷酸（各2.5微克/0.5微升）直接注入左右视上核（SON）。与溶剂组（100%）、混合碱基组或加压素反义处理组的动物相比，Oxt反义组的喷乳反射次数显著减少（降至34.6±4.88%，P<0.001），幼崽体重增加也减少（降至18.8±6.98%，P<0.03），而溶剂组、混合碱基组和加压素反义处理组之间无差异。然而，开始哺乳的时间没有变化。与哺乳前的值相比，所有四组在哺乳开始30分钟后血浆Oxt均显著升高（溶剂组升至325±117%；混合碱基组升至258±48.2%；加压素反义组升至330±55.7%），但在Oxt反义处理的大鼠中这种升高不太明显（升至157±20.5%；与加压素反义组相比，P<0.05）。与哺乳期间这些神经内分泌功能的变化相反，各组垂体后叶和视上核中Oxt以及加压素的含量和Oxt免疫反应性并无差异。我们的数据表明，注入视上核的Oxt反义寡核苷酸对神经内分泌、与哺乳相关的参数有快速且特异性的影响，这并非由于下丘脑 - 神经垂体系统中Oxt储备耗尽所致。
