Changes in the gene expression of steroidogenic enzymes in the brain of morphine dependence rats / 中华麻醉学杂志

ABSTRACT

Objective To investigate the expression of mRNAs for cholesterol side chain cleavage enzyme (p450 scc), 17?-hydroxylase / C17-20 lyase (P450 C17) and 3?-hydroxysteroid dehydrogenase (3?-HSD) in frontal cortex, amygdala, hippocampus, striatum and midbrain of morphine dependence rats.Methods Twenty-one male SD rats were randomly divided into 3 groups with 7 animals in each group (1) control group (group C) ; (2) morphine dependence group (group D) and (3) morphine withdrawal group (group W). In group D and W the animals were given intraperitoneally increasing doses of morphine starting from 5 mg?kg-1 to 10, 15, 20, 30, 40 and 50 mg?kg-1 twice a day for 7 days. In group C the animals were given normal saline instead of morphine. In group C and D the animals were decapitated 1 h after last injection. In group W naloxone 2 mg?kg-1 was given 1h after last morphine injection, then the animals were decapitated 30 min after withdrawal symptoms were observed. The brains were immediately removed and the frontal cortex, amygdala, hippocampus, striatum and midbrain were separated. The expression of mRNAs for the three steroidogenic enzymes in the different brain regions of rats were determined by RT-PCR.Results The expression of P450scc mRNA in striatum and 3?-HSD mRNA in amygdala, striatum and frontal cortex decreased in group D compared with group C. The expression of 3?-HSD mRNA increased in morphine withdrawal group compared with group D.Conclusion The gene expression of steroidogenic enzymes decreases in some brain regions of morphine dependence rats, suggesting that endogenous neurosteroids might be involved in morphine dependence.