Purpose

Brain functional and physiological plasticity is essential to combat dynamic environmental challenges. The rhythmic dopamine signaling pathway, which regulates emotion, reward and learning, shows seasonal patterns with higher capacity of dopamine synthesis and lower number of dopamine transporters during dark seasons. However, seasonal variation of the dopamine receptor signaling remains to be characterized.

Methods

Based on a historical database of healthy human brain [¹¹C]raclopride PET scans (n = 291, 224 males and 67 females), we investigated the seasonal patterns of D2/3 dopamine receptor signaling. Daylength at the time of scanning was used as a predictor for brain regional non-displaceable binding of the radiotracer, while controlling for age and sex.

Results

Daylength was negatively correlated with availability of D2/3 dopamine receptors in the striatum. The largest effect was found in the left caudate, and based on the primary sample, every 4.26 h (i.e., one standard deviation) increase of daylength was associated with a mean 2.8% drop (95% CI -0.042 to -0.014) of the receptor availability.

Conclusions

Seasonally varying D2/3 receptor signaling may also underlie the seasonality of mood, feeding, and motivational processes. Our finding suggests that in future studies of brain dopamine signaling, especially in high-latitude regions, the effect of seasonality should be considered.

中文翻译：

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人脑 D2/3 多巴胺受体可用性的季节性变化

目的

大脑功能和生理可塑性对于应对动态环境挑战至关重要。调节情绪、奖励和学习的节律性多巴胺信号通路表现出季节性模式，在黑暗季节多巴胺合成能力较高，多巴胺转运蛋白数量较少。然而，多巴胺受体信号传导的季节性变化仍有待表征。

方法

基于健康人脑 [ ¹¹ C]雷氯必利 PET 扫描的历史数据库（n  = 291，其中 224 名男性和 67 名女性），我们研究了 D2/3 多巴胺受体信号传导的季节性模式。扫描时的日长被用作放射性示踪剂的大脑区域不可移位结合的预测因子，同时控制年龄和性别。

结果

日长与纹状体中 D2/3 多巴胺受体的可用性呈负相关。最大的影响出现在左侧尾状核，并且根据主要样本，日长每增加 4.26 小时（即一个标准差），日照长度就会平均下降 2.8%（95% CI -0.042 至 -0.014）。受体的可用性。

结论

季节性变化的 D2/3 受体信号传导也可能是情绪、进食和动机过程的季节性的基础。我们的发现表明，在未来的大脑多巴胺信号传导研究中，特别是在高纬度地区，应考虑季节性的影响。