Constant light exposure for one month reduced the concentration of melatonin in the plasma of wistar rats.
Constant light up-regulated the mRNA level of Per1, Per2 and dopamine D1 receptor in the striatum.
Constant light up-regulated the mRNA level of Per2 and dopamine D1 receptor in the prefrontal cortex.
Exposure to constant light led to greater preference for oral morphine consumption.
Rats exposed to constant light had more severe morphine withdrawal syndrome.