快猫短视频

A SURPRISE finding in fruit flies suggests that biological clocks may be
involved in cocaine addiction.

Last year, Jay Hirsh and his colleagues at the University of Virginia in
Charlottesville discovered that fruit flies respond to crack cocaine smoke by
grooming and walking in circles. Repeated exposure to the drug made the flies
respond more dramatically to the same doses, the same kind of 鈥渟ensitisation鈥�
found in humans. This kind of reaction is peculiar to drugs like cocaine.

Now Hirsh鈥檚 graduate student Rozi Andretic has found that flies with broken
clocks fail to become sensitised. The researchers report in the current issue of
Science (vol 285, p 1066) that flies missing any one of four biological
clock genes have a constant response to cocaine despite repeated exposures.
鈥淭his is not something that anyone would have predicted,鈥� says Hirsh. 鈥淲e still
find it somewhat surprising.鈥�

Hirsh notes that people with certain psychiatric problems such as bipolar
disorder develop irregular sleep patterns and are more likely to abuse drugs. He
speculates that defects in clock genes could explain the connection. 鈥淭his opens
the possibility that there could be some linkages between these biological
phenomena,鈥� he says.

Other circadian rhythm researchers were surprised by the finding but weren鈥檛
sure where it would lead. Michael Rosbash at Brandeis University in Waltham,
Massachusetts, for example, points out that this is the first time the clock
genes have been implicated in anything other than regulating clocks. 鈥淭he
question is what does it mean,鈥� he says. 鈥淥nly time will tell.鈥�