Expression of genes for neuropeptides and their receptors was also altered (Table 2; Supplementary Table 1). In many cases the expression of the neuropeptide and receptors had parallel changes. Pdyn (prodynorphin) and its receptor Oprk1 were both decreased, as was Pnoc (prepronociceptin) and its receptor Oprl1, galanin and two of its receptors, and Neuromedin B and its receptor. For others, there appeared to be compensatory changes, with the expression of the peptide and its receptors changing in opposite directions. Neuropeptide Y (Npy) was increased (+1.6 fold) but its receptors Npy1r and Npy5r were both decreased (−1.6 fold). There was a 3-fold increase in the gene expression for hypocretin (orexin), but expression of both hypocretin receptors was decreased about 2-fold. Expression of Cck (cholecystokinin) was increased but its B receptor gene was decreased. There was a small decrease in expression of Sst (somatostatin) with decreases in two of its receptors (Sstr1 and Sstr2) and a large increase in a third receptor, Sstr3. The two corticotropin-releasing hormone (Crh) receptors were differentially altered, with Crhr1 increased and Crhr2 decreased.
