2.9 Genomic DNA analysis
To detect the presence of the Oprm1fl/fl andPirt-Cre+/- genes, we performed PCR on genomic DNA obtained from tail samples. Oprm1 primer sequences were 5′-GTTACTGGAGAATCCAGGCCAAGCC-3′ (forward) and 5′-CGCTTGGGAATATCTTGTACCTATGACCA-3′ (reverse). Pirt-Cre primer sequences were 5′-ATCCGTAACCTGGATAGTGAA-3′ (Cre forward), 5′-CAACTTTGTGGTACCCGAAG-3′ (Pirt forward), and 5′-TCCCTGGGACTCATGATGCT-3′ (Pirt reverse).