We found that among G/G mice males displayed higher DAMGO-stimulated [35S]GTPγS binding than females in the cingulate cortex, CPu, thalamus, NAc core and amygdala; however, no sex differences were observed among A/A mice. These results indicate that the sex differences are limited to the G/G mice in these regions. In future studies, it may be important to examine if sex differences are present in the G/G mice in behavioral endpoints mediated by the MOPR in these brain regions.
