AIM To explore gallbladder circadian rhythm (GCR) and the cholagogic action of Yin Chen Hao Ta(YCHT).METHODS Ultrasonography of rabbit gallbladder at 17:00 to 19:00, 23:00 to 01:00, 05:00 to 07:00 m11:00 to 13:00 showed its maximum area (MA), dilatation rate (GDR) and systole rate. Its movemecircadian rhythm (MCR) and the effect of YCHT on gallbladder and the relationship with time weobserved and evaluated.RESULTS The results showed that gallbladder area changed with time, which varied from 11:00 to 13:1>23:00 to 01:00 and 05:00 to 07:00> 17:00 to 19:00 (P<0.01, F=9.13 vs. control by analysisvariance). The cholagogic action at 23:00 to 01:00 and 17:00 to 19:00 was better than that at 11:00 to 13:and 05:00 to 07:00.CONCLUSION The gallbladder movement action (GMA) showed markedly circadian rhythm. Tcholagogic action of YCHT at 23:00 to 01:00 and 17:00 to 19:00 is better.

日间与夜间靶控输注异丙酚镇静效果的比较

Objective To compare the hypnotic effects of propofol administered by target-controlled infusion (TCI in daytime and nighttime,in order to explore the effect of circadian rhythm on the sedative effect of propofol.Methods Sixty-five male ASA Ⅰ or Ⅱ patients,aged 18-55 years,with the body mass index (BMI) of 18.5-24.9 kg/m2,undergoing emergency minor hand surgery were divided into two groups according to the time of the day when they received TCI of propofol:daytime group (from 07:01 to 19:00) and nighttime group (from 19:01 to 07:00).The pharmacokinetic parameters proposed by Schnider et al.which suggested the effect-site concentration (Ce) was used.Four Ces of propofol were set at 0.8,1.2,2.0 and 4.0 μg/ml,respectively.Ce was increased step by step and each Ce was maintained for 5 minutes.The level of sedation at each Ce was assessed by bispectral index (BIS) and observer's assessment of alertness/sedation (OAA/S) scores.BIS values and Ces of propofol were recorded and compared between the two groups when the patients lost consciousness (OAA/S score =2).Results There were 28 and 30 patients in daytime and nighttime groups,respectively.When Ces were 1.2 and 2.0 μg/ml,the BIS values were significantly lower in the nighttime group than in the daytime group.There was no significant difference in BIS values between the two groups when Ces were 0.8 and 4.0 μg/ml.When the patients lost consciousness (OAA/S =2),the BIS value was comparable between the two groups,but Ce was significantly lower in the nighttime group than in the daytime group.Conclusion The hypnotic effect of propofol is greater during night time than during day time.

The circadian clock and sleep are essential for human physiology and behavior; deregulation of circadian rhythms impairs health and performance. Circadian clocks and sleep evolved to adapt to Earth’s environment, which is characterized by a 24-hour light–dark cycle. Changes in gravity load, lighting and work schedules during spaceflight missions can impact circadian clocks and disrupt sleep, in turn jeopardizing the mood, cognition and performance of orbiting astronauts. In this review, we summarize our understanding of both the influence of the space environment on the circadian timing system and sleep and the impact of these changes on astronaut physiology and performance.