Hart J L, Freas W, Muldoon S M
Am J Physiol. 1986 Nov;251(5 Pt 2):H1000-8. doi: 10.1152/ajpheart.1986.251.5.H1000.
Activity of the vascular neuroeffector junction was examined in pregnant (PG) and nonpregnant (NPG) rats to determine whether changes could account for the reported alterations in sympathetic control of the maternal circulation. Caudal and mesenteric arteries were removed from NPG and 19-21 day PG rats and prepared for isometric tension recording. Frequency-response measurements were obtained, followed by norepinephrine (NE) and tyramine concentration-response measurements. The caudal artery developed more tension in response to NE, tyramine, and electrical stimulation than did the mesenteric artery; however, there were no differences between vessels from NPG and PG rats. NE content, [3H]NE accumulation, and effects of plasma on [3H]NE accumulation of NPG and PG caudal arteries were also compared and found to be similar. Therefore, vascular neuroeffector functions of NE release, receptor sensitivity, and NE accumulation are not modified in the rat during pregnancy. Changes in sympathetic control of the maternal circulation are likely to be dependent on alterations at sites other than the neuroeffector junction.
研究了妊娠（PG）和未妊娠（NPG）大鼠的血管神经效应器连接的活性，以确定这些变化是否能解释所报道的母体循环交感神经控制的改变。从NPG和妊娠19 - 21天的PG大鼠中取出尾动脉和肠系膜动脉，制备用于等长张力记录。获得频率 - 反应测量结果，随后进行去甲肾上腺素（NE）和酪胺浓度 - 反应测量。与肠系膜动脉相比，尾动脉对NE、酪胺和电刺激产生的张力更大；然而，NPG和PG大鼠的血管之间没有差异。还比较了NPG和PG尾动脉的NE含量、[³H]NE摄取以及血浆对[³H]NE摄取的影响，发现它们相似。因此，在大鼠妊娠期间，NE释放、受体敏感性和NE摄取的血管神经效应器功能未发生改变。母体循环交感神经控制的变化可能取决于神经效应器连接以外部位的改变。
