The new data confirm observations from studies of people who work night shifts, says Richard Stevens of the University of Connecticut Health Centre. Mood disorders join a growing list of problems, including cancer, obesity and diabetes—that can occur when light throws life out of balance by disturbing the biological clock and its timing of daily rhythms.
In the new study, Tracy Bedrosian and Randy Nelson of Ohio State University exposed mice to normal light and dark cycles for four weeks. For the next four weeks, half of the mice remained on this schedule, and the rest received continuous dim light throughout their night. Compared with mice exposed to normal nighttime darkness, those getting dim light at night lost their strong preference for sweet drinks,“a sign they no longer get pleasure out of activities they once enjoyed,” Bedrosian says.
In a second test, mice were clocked on how long they actively tried to escape a pool of water. Those exposed to night lights stopped struggling and just floated in the water, a sign of “behavioural despair”,10 times as long as the mice that had experienced normal nighttime darkness. All symptoms of depression disappeared within two weeks of the mice returning to a normal lightdark cycle, the researchers report. The scientists also could quash the behavioural symptoms by injecting (注射)the brains of animals with a drug that prohibits the activity of certain molecules linked with human depression. This finding further suggests that light at night may cause something related to depression.
【2017届重庆市高考英语一轮复习阅读理解选编精练:122(含解析)】相关文章:
★ 湖南省汝城二中2014届高考英语一轮复习阅读训练 (59)
★ 浙江省湖州市2014高考英语完形填空一轮(暑假)精炼(7)含答案
★ 【人教版】2014届高考英语一轮复习指导考点针对练:必修1 unit4《Earthquakes》
最新
2017-04-24
2017-04-24
2017-04-24
2017-04-24
2017-04-21
2017-04-21