Table 1.

Antibodies against opioid receptors used for immunohistochemistry.

Antibody to	Immunogen	Source	Dilution
μ-opioid receptor (MOR)	Synthetic peptide for the C-terminus of rat μ-opioid receptor	Millipore (St. Louis, MO) Rabbit polyclonal antibody No. AB5511	1:100,000
δ-opioid receptor (DOR)	Synthetic peptide for amino acids 358–372 of rat δ-opioid receptor	Abcam (Cambridge, UK) Rabbit polyclonal antibody No. Ab10272	1:10,000
κ-opioid receptor (KOR)	Synthetic peptide for amino acids 366–380 of human κ-opioid receptor	Abcam (Cambridge, UK) Rabbit polyclonal antibody No. Ab10283	1:10,000