title: Opioid receptor expression in human brain and peripheral tissues using absolute quantitative real-time RT-PCR.
abstract: BACKGROUND
  The actions of endogenous opioid peptides are mediated by 3 main classes of opioid receptors; mu (MOR), kappa (KOR), and delta (DOR).
  
  
  METHODS
  We developed an absolute quantitative real-time reverse transcriptase PCR (AQ-rt-RT-PCR) assay to quantify MOR, DOR, and KOR mRNA in 22 human tissues.
  
  
  RESULTS
  MOR mRNA was greatly enriched (12-20×10(6)copies/μg) in the cerebellum, nucleus accumbens, and caudate nucleus; moderate (6×10(6)copies/μg) in the dorsal root ganglion, spinal cord, and adrenal gland; low (2×10(4)copies/μg) in the pancreas and small intestine; and absent in the lung, spleen, kidney, heart, skeletal muscle, liver, and thymus. High levels (>8.8×10(6)copies/μg) of DOR mRNA were expressed in the brain and dorsal root ganglion; moderate (1.5×10(6)copies/μg) in the adrenal gland and pancreas; low (2×10(4)-6.5×10(5)copies/μg in the cerebellum, spinal cord, small intestine, skeletal muscle, thymus, lung, and kidney); and very low (3.8×10(3)copies/μg) in the heart. DOR mRNA was not detected in the spleen or liver. KOR mRNA was moderate (1×10(6)copies/μg) in brain regions and dorsal root ganglion, but low (1.6-7×10(5)copies/μg) in the cerebellum, temporal lobe and all other peripheral tissues.
  
  
  CONCLUSIONS
  Our data demonstrate that the AQ-rt-RT-PCR is a highly reproducible and precise method to study the expression of opioid receptors in various tissues and under different disease conditions.
authors.affiliation: Institute of Neuroimmune Pharmacology, Seton Hall University, 400 South Orange Avenue, South Orange, NJ 07079, USA.
authors.forename: Jinsong
authors.initials: J
authors.lastname: Peng
authors.forename: Sraboni
authors.initials: S
authors.lastname: Sarkar
authors.forename: Sulie L
authors.initials: SL
authors.lastname: Chang
mesh_terms: D000293:Adolescent; D000328:Adult; D001921:Brain / Q000378:metabolism*; D005260:Female; D005727:Ganglia, Spinal / Q000378:metabolism; D006801:Humans; D008297:Male; D008875:Middle Aged; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D060888:Real-Time Polymerase Chain Reaction / Q000379:methods*; D017465:Receptors, Opioid, delta / Q000235:genetics / Q000378:metabolism*; D017473:Receptors, Opioid, kappa / Q000235:genetics / Q000378:metabolism*; D017450:Receptors, Opioid, mu / Q000235:genetics / Q000378:metabolism*; D013116:Spinal Cord / Q000378:metabolism
chemical_list: D012333:RNA, Messenger; D017465:Receptors, Opioid, delta; D017473:Receptors, Opioid, kappa; D017450:Receptors, Opioid, mu