Oprm1^tm2.1Shlz

Exon 3b was replaced with on in which nulceotide substitutions result in the amino acid substitutions of alanine for 01 serine or threonine: T354A (ACT to GCC), S355A (TCC to GCC), S356A (TCC to GCC); T357A (ACA to GCA); S363A (TCT to GCC); T370A (ACT to GCC); S375A (TCC to GCC); T376A (ACG to GCC); T379A (ACA to GCA); T383A ( ACT to GCC). Cre-mediated removed a floxed neomycin resistance cassette inserted downstream of the modified exon 3b.