[Sex and changes in mu-opioid receptor density under hypoxia]

The opioid system modulates the growth and development of CNS. Hypoxia increases endogenous opioids significantly. The density and distribution of mu-opioid receptors in MPOA is cyclical and sexually dimorphic. To test the hypothesis that perinatal hypoxia affects the development of the opioid receptor system in fetus brain in both sexes differentially, we performed the following study. We divided 24 pregnant Sprague-Dawley rats to two treatment groups and control group. We exposed one group (CH) to chronic prenatal hypoxia (10.5% O2) continuously 24 h/day and second group (AH) to acute, intermittent hypoxia (9.0% O2) 6 h/day from day E15 to E20. We analyzed the brain regions: CPu, ZG, NA, OT, MMPoA, LMPoA by quantitative autoradiography following incubation with (3H) DAMGO. We didn't notice any significant changes in mu-opioid receptor density between sexes in selected brain regions. We found mu-opioid receptor a significant changes in mu-opioid receptor of all brain regions in female group.