Oti Takumi, Sakamoto Tatsuya, Sakamoto Hirotaka
Department of Biological Sciences, Faculty of Science, Kanagawa University, Hiratsuka, Japan.
Ushimado Marine Institute (UMI), Graduate School of Natural Science and Technology, Okayama University, Setouchi, Japan.
Commun Integr Biol. 2021 Mar 29;14(1):55-60. doi: 10.1080/19420889.2021.1902056.
Oxytocin is produced in the hypothalamus and stimulates uterine contraction and milk ejection. While many people consider oxytocin to be a female hormone, it is reported that, in men, the plasma oxytocin level increases markedly after ejaculation. However, this aspect of oxytocin physiology is poorly understood. The spinal ejaculation generator (SEG), which expresses the neuropeptide, gastrin-releasing peptide (GRP), can trigger ejaculation in rats. Therefore, we focused on systemic effects of oxytocin on the GRP/SEG neuron system in the lumbar spinal cord controlling sexual activity in male rats. We found that systemic administration of oxytocin significantly shortened the latency to the first mount, intromission and ejaculation during male copulatory behavior. In addition, the local oxytocin level in the lumbar cord was significantly higher in males than in females. Histological analysis showed that oxytocin-binding is apparent in spinal GRP/SEG neurons. We therefore conclude that oxytocin influences male sexual activity the SEG.
催产素在下丘脑产生，可刺激子宫收缩和乳汁排出。虽然许多人认为催产素是一种女性激素，但据报道，男性射精后血浆催产素水平会显著升高。然而，催产素生理学的这一方面尚不清楚。表达神经肽胃泌素释放肽（GRP）的脊髓射精发生器（SEG）可触发大鼠射精。因此，我们关注了催产素对控制雄性大鼠性活动的腰段脊髓中GRP/SEG神经元系统的全身作用。我们发现，全身给予催产素可显著缩短雄性交配行为中首次爬跨、插入和射精的潜伏期。此外，雄性腰段脊髓中的局部催产素水平显著高于雌性。组织学分析表明，脊髓GRP/SEG神经元中存在明显的催产素结合。因此，我们得出结论，催产素通过SEG影响雄性性活动。
