Depressive symptoms are diagnosed by physicians using scales but their pathophysiology is unclear. Low serotonin (5–HT) levels play an important role in depression, and the 5–HT transporter (5–HTT) is an important regulator of plasma serotonin levels and reuptake. Additionally, the 5–HTT gene-linked polymorphic region (5–HTTLPR) is associated with depression. The aim was to clarify the roles of plasma serotonin levels in plasma and the 5HTTPLR polymorphism in depressive symptoms in older adults. A total of 84 older adult participants were evaluated. Depressive symptoms were measured using the Center for Epidemiologic Studies Depression Scale of 20 items (CESD–20). The plasma serotonin levels were determined by ELISA, and the 5–HTTLPR genotype was analyzed by PCR. Depressive symptoms were present in 39.3% (N = 33) of the participants. The median plasma serotonin level was 204.34 ng/mL (SD = 93.88). A significant correlation was found between the CESD–20 scale and plasma serotonin levels (r = –.256; p = .019). Low serotonin levels were associated with the presence of depressive symptoms (p = .001). The 5–HTTLPR analysis showed that of the 84 older adults, 35.7% had the SS genotype, 10.7% had the LL genotype, and 53.6% were heterozygous. The 5–HTTLPR polymorphism was not associated with depressive symptoms (p = .587) and plasma serotonin levels (p = 0.391). Depressive symptoms correlate with low serotonin levels in plasma, but not with the 5–HTTLPR polymorphism in older Mexican adults.

中文翻译：

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抑郁症状与血浆血清素水平低有关，但与老年人的 5-HTTLPR 基因型无关

抑郁症状由医生使用量表诊断，但其病理生理学尚不清楚。低血清素 (5-HT) 水平在抑郁症中起重要作用，而 5-HT 转运蛋白 (5-HTT) 是血浆血清素水平和再摄取的重要调节剂。此外，5-HTT 基因连锁多态区 (5-HTTLPR) 与抑郁症有关。目的是阐明血浆中血清素水平和 5HTTPLR 多态性在老年人抑郁症状中的作用。共评估了 84 名老年参与者。使用流行病学研究中心抑郁量表 20 项 (CESD-20) 测量抑郁症状。通过ELISA测定血浆5-羟色胺水平，并通过PCR分析5-HTTLPR基因型。39.3% 出现抑郁症状（ñ= 33) 的参与者。中位血浆血清素水平为 204.34 ng/mL (标清= 93.88）。在 CESD-20 量表和血浆血清素水平之间发现了显着的相关性（r= –.256;p= .019)。低血清素水平与抑郁症状的存在有关（p= .001)。5-HTTLPR分析显示，84名老年人中，SS基因型占35.7%，LL基因型占10.7%，杂合子占53.6%。5-HTTLPR 多态性与抑郁症状无关（p= .587) 和血浆血清素水平 (p= 0.391)。抑郁症状与血浆中血清素水平低相关，但与墨西哥老年人的 5-HTTLPR 多态性无关。