Abstract: ObjectiveTo investigate the effects of vaccinium bracteatum thunb leaf ethanol extract(VEE)on mental fatigue and its mechanism in rats.MethodsThe rat mental fatigue model was established by sleep deprivation(SD)through flower-pot,and then spontaneous movement activity,learning and memory ability were measured by spontaneous movement box and Morris water maze(MWM).In the mean time,the content of neurotransmitters NE,E,DA and 5-HT in brain stem were also determined with electrochemical detector or fluorescence detector by High Performance Liquid Chromatography (HPLC)method respectively after praxiology test.ResultsThe latency period and total path in MWM was(10.6±2.8)s, (13.0±8.2)s,(11.2±6.4)s,(6.9±2.4)s,and(1 490±380)mm,(2 392±1 612)mm,(2 102±1 321)mm,(1 167±364) mm in normal control(NC)group,low,middle and high dose V EE group,respectively,decreased obviously compared with the control sleep deprivation(C-SD)group(19.2±4.1)s,(3 455±843)mm(P<0.05 or P<0.01).Compared with C-SD group(51±11)high dose VEE group had higher scores(70±9)in open field test(P<0.05).The content of NE,DA and 5-HT in brain stem were(0.3 467±0.0 827)ng/mg,(0.0 131±0.0 033)ng/mg and(12.1 820±1.0 835)ng/mg in C-SD group.Elevated content of NE(0.5408±0.2191)ng/mgand DA(0.0 304±0.0 058)ng/mgand decreased content of 5-HT(10.0300±0.8538)ng/mgappeared when treated with high dose VEE(P<0.05).ConclusionThe VEE could remarkably relieve the mental fatigue induced by SD.Its mechanism might be related to the adjustment of brain stem monoamine neurotransmitters.