Obál F, Kapás L, Krueger J M
Department of Physiology, A. Szent-Györgyi Medical University, Szeged, Hungary.
Physiol Behav. 1998 Jun 1;64(3):261-6. doi: 10.1016/s0031-9384(98)00074-2.
Rats 4 to 7 days after weaning received intraperitoneal (i.p.) injections of vehicle (baseline day), and either serum (2 mL of lyophilized rabbit serum), 140 mg of rat albumin, or hyperosmotic NaCl (experimental day). Injections were given 1 h before light onset. Sleep-wake activity and cortical brain temperature were recorded during the subsequent 12-h light period. The intensity of non-rapid eye movement sleep (NREMS) was characterized by the power density values of the electroencephalogram slow-wave activity. The sera and albumin preparations enhanced both NREMS and slow-wave activity for 5 to 6 h starting during Hour 2 after light onset. Rapid eye movement sleep (REMS) tended to decrease. Modest (0.6 degrees C maximum deviation) biphasic changes were observed in cortical brain temperature with initial decreases for 3 h followed by rises between Hours 3 and 9 of the light period. There were no differences in the sleep responses to albumin between male and female rats. Albumin also enhanced NREMS in young rats on a protein-rich diet. A significant negative correlation was found between the NREMS promoting activity of albumin injections and the body weight of the rats. NaCl solution with the same osmolarity as that of the albumin solution failed to alter sleep. I.p. albumin injection elicited significant increases in the concentrations of cholecystokinin-like immunoreactivity in the plasma. Sleep-promoting materials (hormones) in the albumin fraction, the calorigenic or nutritional value of proteins, the release of somnogenic cytokines by albumin, or endogenous humoral mechanisms stimulated by proteins (e.g., cholecystokinin or the somatotropic axis) might mediate the enhanced sleep after albumin.
断奶后4至7天的大鼠接受腹腔内（i.p.）注射溶媒（基线日），以及血清（2毫升冻干兔血清）、140毫克大鼠白蛋白或高渗氯化钠（实验日）。在光照开始前1小时进行注射。在随后的12小时光照期间记录睡眠-觉醒活动和皮质脑温。非快速眼动睡眠（NREMS）的强度通过脑电图慢波活动的功率密度值来表征。血清和白蛋白制剂在光照开始后第2小时开始增强NREMS和慢波活动5至6小时。快速眼动睡眠（REMS）有减少的趋势。在皮质脑温中观察到适度的（最大偏差0.6摄氏度）双相变化，最初3小时下降，随后在光照期的第3至9小时上升。雄性和雌性大鼠对白蛋白的睡眠反应没有差异。白蛋白也增强了高蛋白饮食的幼鼠的NREMS。发现白蛋白注射的NREMS促进活性与大鼠体重之间存在显著的负相关。与白蛋白溶液渗透压相同的氯化钠溶液未能改变睡眠。腹腔内注射白蛋白引起血浆中胆囊收缩素样免疫反应性浓度的显著增加。白蛋白组分中的促睡眠物质（激素）、蛋白质的产热或营养价值、白蛋白释放促睡眠细胞因子或蛋白质刺激的内源性体液机制（如胆囊收缩素或生长激素轴）可能介导了白蛋白注射后睡眠增强。
