Altered expression of circadian clock gene, mPer1, in mouse brain and kidney under morphine dependence and withdrawal

Table 1 Cosinor analysis of mPER1 expression.

Group	P	MESOR ± SE (IOD)	Amplitude ± SE (IOD)	Acrophase (95 %CL) Hour
Expression of m PER1 in the brains
Con	< 0.001	1010.8 ± 47.2	728.6 ± 66.8	-343.5° (-333, -354) 22:54
MD	< 0.001	1609.5 ± 149.9*	1263.1 ± 212.0*	-256.1° (-237, -275)* 17:04
MW	< 0.001	1221.6 ± 66.6	832.6 ± 94.3	-348.6° (-335, 0) 23:24
Expression of mPER1 in the kidneys
Con	< 0.001	2559.2 ± 110.3	1368.4 ± 156.1	-47.7° (-34, -60) 03:11
MD	0.538	113.1 ± 15.9#	25.4 ± 22.5#	-148.5° (0, 0)# 09:54
MW	0.602	396.8 ± 45.9#	66.0 ± 64.9#	-350.5° (0, 0)# 23:22

* p < 0.05 compared with control or MW groups, separately, tested by the parameters of cosinor designed by Bingham et al. [18]. ^# p < 0.05 compared with control group, tested by the parameters of cosinor. The mPER1 protein expression level is represented by the IOD, which was the value of immunoreactivity of mPER1 in tissues reacting with mPER1 antibody determined by image pro plus software.
Con: Control; MD: Morphine-dependent; MW: Morphine-withdrawal. P in the table is the p-value of circadian rhythm coming from cosine function fitting. The hour in the table is the time of clock hour for the acrophase of the fitted cosine function.