Table II.

Number of differentially expressed genes.

Group comparison	Upregulated	Downregulated
MO/C	162	16
MOMa/C	290	15
Ma/C	476	71

Standard selection criteria to identify differentially expressed genes are as follows: i) log₂ |Fold change|≥1 and P<0.05; ii) log₂ ratios=‘NA’ and the differences of intensity between the two samples ≥1000. Detail gene lists were be provided by request. C, control (saline infusion/vehicle injection/saline challenge); Mo, morphine (morphine infusion/vehicle injection/morphine challenge); Ma, melatonin (morphine infusion/melatonin injection/saline challenge); MOMa, (morphine infusion/melatonin injection/morphine challenge).