Laurienti Paul J, Field Aaron S, Burdette Jonathan H, Maldjian Joseph A, Yen Yi-Fen, Moody Dixon M
Department of Radiology, Wake Forest University School of Medicine, Winston-Salem, North Carolina 27157-1022, USA.
Neuroimage. 2002 Oct;17(2):751-7.
Caffeine is the most widely used stimulant in the world. The stimulant effects of caffeine are mediated through its antagonistic properties on neuronal adenosine receptors. In addition, caffeine blocks neurovascular adenosine receptors and decreases cerebral perfusion. Although the effects of caffeine on blood oxygenation level-dependent (BOLD) functional magnetic resonance imaging measures are extremely important, there are few studies addressing this issue in the literature. Because chronic caffeine use causes an upregulation of adenosine receptors, the differential effects of caffeine in low and high users is of particular interest. The present study was designed to test the hypothesis that caffeine has differential effects on the BOLD signal in high and low caffeine users. We demonstrated that the BOLD signal change in visual cortex was significantly greater in high users than in low users in the presence of caffeine. In addition, the magnitude of the BOLD signal was significantly correlated with caffeine consumption. We propose that the outcome observed here was due to an upregulation of adenosine receptors in high users, resulting in differential contributions of the neural and vascular effects of adenosine in the two study populations.
咖啡因是世界上使用最广泛的兴奋剂。咖啡因的兴奋作用是通过其对神经元腺苷受体的拮抗特性介导的。此外，咖啡因会阻断神经血管腺苷受体并减少脑灌注。尽管咖啡因对血氧水平依赖（BOLD）功能磁共振成像测量的影响极为重要，但文献中很少有研究涉及这个问题。由于长期使用咖啡因会导致腺苷受体上调，因此咖啡因在高使用者和低使用者中的差异效应尤其令人感兴趣。本研究旨在检验咖啡因对高咖啡因使用者和低咖啡因使用者的BOLD信号有不同影响这一假设。我们证明，在有咖啡因存在的情况下，高使用者视觉皮层的BOLD信号变化显著大于低使用者。此外，BOLD信号的幅度与咖啡因摄入量显著相关。我们认为，此处观察到的结果是由于高使用者中腺苷受体上调，导致腺苷在两个研究人群中的神经和血管效应有不同贡献。
