| Objectives:Most organisms living on earth show circadian rhythm that is endogenously controlled by circadian clock. Recently, some molecular studies of circadian clock have shown that the phase of circadian protein expressions in brain and peripheral clocks could be changed by exogenous stimuli. To elucidate whether morphine is involved in the changed phase of circadian rhythm, we examined the protein expression of one of crucial circadian clock genes, mPe1, under morphine-dependence and withdrawal in mice.Methods:Male BALB/C mice, 4-6 weeks old, were used in the experiments. Mice were randomly divided into three groups, including Control (Con), Morphine -dependent (MD), Morphine- withdrawal (MW). Conditional place preference (CPP) paradigm used to investigate the effect of three groups on morphine administration in mice. The three groups were sacrificed at 0 am, 4 am, 8 am, 12 pm, 4 pm, and 8 pm respectively. The protein of brains and kidneys were isolated from these tissues for western blotting. The brains and kidneys of other mice were dehydrated and blocked in paraffin. Then, serial sections of 4nm were cut and processed for HE staining and immunohistochemistry.Results:Our results demonstrated that the expression of mPERl showed strong circadian pattern in the brains of the control (Con), the morphine-dependent (MD) and the morphine-withdrawal (MW) mice, respectively. However, the phase of mPERl expression in the brains displayed obviously different between the MD and the Con mice, and the expression of mPERl in MD was increased and the phase of circadian rhythm of it shifted ahead compared with Con (p<0.05). But, the expression of mPER1 in the brains of mice did not show statistical difference between the MW and... |
PDF Full Text Request