Nguyen T T, Tseng Y T, McGonnigal B, Stabila J P, Worrell L A, Saha S, Padbury J F
Department of Pediatrics, Brown University School of Medicine, Women and Infants' Hospital of Rhode Island, Providence, USA.
Placenta. 1999 Jan;20(1):3-11. doi: 10.1053/plac.1998.0348.
The biogenic amine transporters are part of a large family of plasma membrane transporters. These carriers mediate the re-uptake of neurotransmitters from the synaptic cleft and plasma compartments. Re-uptake process is inhibited by drugs like cocaine, fluoxetine and tricyclic antidepressants. There are specific transporters for norepinephrine, epinephrine, dopamine and serotonin. The placenta expresses the norepinephrine and serotonin transporters, which is unusual as they are otherwise expressed predominantly in neuronal tissue. Fetal catecholamine clearance rate is higher than under any other physiological conditions and is mediated in large measure by the placental transporters. The high intrauterine catecholamine secretion and clearance rates are part of the unique fetal neuroendocrine milieu. They condition the fetus to a high capacity for catecholamine secretion in the early postnatal period when elevated sympathoadrenal system activity is vital for postnatal survival. Because of the prominent catecholamine clearance rate, the fetus is vulnerable to the adverse effects of re-uptake inhibitors. Understanding the mechanisms of expression and regulation of placental biogenic amine transporters is important to the pathobiology of fetal conditions associated with elevated catecholamine levels or intrauterine exposure to uptake inhibitors like cocaine.
生物胺转运体是质膜转运体大家族的一部分。这些载体介导神经递质从突触间隙和血浆区室的再摄取。再摄取过程会受到可卡因、氟西汀和三环类抗抑郁药等药物的抑制。存在去甲肾上腺素、肾上腺素、多巴胺和血清素的特异性转运体。胎盘表达去甲肾上腺素和血清素转运体，这很不寻常，因为它们通常主要在神经组织中表达。胎儿儿茶酚胺清除率高于任何其他生理条件下的清除率，并且在很大程度上由胎盘转运体介导。子宫内儿茶酚胺的高分泌和清除率是独特的胎儿神经内分泌环境的一部分。它们使胎儿在出生后早期具有高儿茶酚胺分泌能力，此时交感肾上腺系统活动增强对出生后的生存至关重要。由于显著的儿茶酚胺清除率，胎儿易受再摄取抑制剂的不利影响。了解胎盘生物胺转运体的表达和调控机制对于与儿茶酚胺水平升高或子宫内暴露于可卡因等摄取抑制剂相关的胎儿疾病的病理生物学很重要。
