Effects of morphine dependence and withdrawal on levels of neurosteroids in rat brain.

AIM To investigate the effects of morphine dependence and withdrawal on the concentrations of neurosteroids in rat brain. METHODS A method of simultaneous quantification of neurosteroids by gas chromatography-mass spectrometry (GC-MS) had been established. RESULTS The chronic morphine administration (ip) resulted in a marked decrease in the brain concentrations of pregnenolone (PREG), progesterone (PROG), and pregenenolone sulfate (PREGS) in rats killed 6 h after the last treatment. In contrast, there were no significant effects of morphine dependence on the brain concentrations of allopregnanolone (AP), dihydroepiandrosterone (DHEA), and dihydroepiandrosterone sulfate (DHEAS). Naloxone-induced withdrawal produced a significant increase in the concentrations of PREG, PROG, AP, DHEA, PREGS, and DHEAS as compared with the control group. CONCLUSION Morphine dependence and withdrawal affected the concentrations of neurosteroids in rat brain, which suggests that endogenous neurosteroids in brain might be related to the development of morphine dependence and withdrawal.