Department of Obstetrics and Gynecology, Lund University Hospital, 221 85 Lund, Sweden.
Mol Hum Reprod. 2003 Jul;9(7):389-94. doi: 10.1093/molehr/gag052.
The uterus is innervated by adrenergic sympathetic fibres, and the endometrium has a capability for endogenous monoamine synthesis. Extracellular monoamine levels are regulated primarily through re-uptake by specific membrane-bound transporter proteins dopamine transporter (DAT), norepinephrine transporter (NET) and serotonin transporter (SERT). Intracellular storage of monoamines involves vesicular transporter proteins (VMAT1 and VMAT2). This study explored gene expression of the monoamine transporters in normal endometrium throughout the menstrual cycle and early decidua. In-situ hybridization histochemistry revealed three general classes of expression patterns: (i). epithelial expression of NET mRNA; (ii). increasing stromal expression of VMAT2 mRNA in the proliferative phase; and (iii). increasing epithelial expression of VMAT2 mRNA during the secretory phase. Real time PCR showed low expression levels of NET in all phases of the endometrial cycle and a higher expression of VMAT2 mRNA in the mid-secretory phase. Our results suggest that several monoamine transporters may have menstrual cycle phase-specific functions in endometrial biology by maintaining adequate levels of monoamines. Re-uptake and regulated release of monoamines may also modulate several steps of the reproductive processes such as embryo implantation and decidua formation.
子宫由肾上腺素能交感神经纤维支配，子宫内膜具有内源性单胺合成的能力。细胞外单胺水平主要通过特定的膜结合转运蛋白多巴胺转运体（DAT）、去甲肾上腺素转运体（NET）和 5-羟色胺转运体（SERT）的再摄取来调节。单胺的细胞内储存涉及囊泡转运蛋白（VMAT1 和 VMAT2）。本研究探讨了正常子宫内膜和早孕蜕膜中单胺转运体的基因表达。原位杂交组织化学显示出三种一般的表达模式：（i）NET mRNA 的上皮表达；（ii）在增殖期，VMAT2mRNA 的基质表达增加；（iii）在分泌期，VMAT2mRNA 的上皮表达增加。实时 PCR 显示 NET 在子宫内膜周期的所有阶段表达水平较低，而 VMAT2mRNA 在中期分泌期表达水平较高。我们的结果表明，几种单胺转运体可能通过维持适当的单胺水平，在子宫内膜生物学中具有月经周期特异性功能。单胺的再摄取和调节释放也可能调节生殖过程的几个步骤，如胚胎着床和蜕膜形成。
