Table 1.

The quantitative real-time PCR primers of different genes.

Gene	Upstream primer	Downstream primer	Length of PCR product	Referenced GenBank no.
β-Actin	5′-ACACGGTGCCCATCTACGA-3′	5′-CCTTGATGTCACGGACGATTT-3′	159 bp	AF481159
PENK	5′-GGCGACCGTGAGGGCAGAATG-3′	5′-GCAGGTTTCCCAGGTCTTGAG-3′	139 bp	NM174141
POMC	5′-GGCGGCCGAGAAGAAGGAC-3′	5′-CTTGATGATGGCGTTTTTGA-3′	148 bp	NM001009266
PDYN	5′-CTTTCCTCACTCCCTTCACCG-3′	5′-TCTCCACCAGGCTGCTACTCA-3′	186 bp	NM174139
δ-receptor	5′-TGCTCTCCATTGACTACTACA-3′	5′-AAGAGGAACACGGCAGATTTTG-3′	289 bp	NM001191148
μ-receptor	5′-AGTGTGTTATGGGCTGATGA-3′	5′-GCGTCCAGCAGACAATGAACACAG-3′	137 bp	AF266480
κ-receptor	5′-CGTCTTCGTCGTCTGCTGG-3′	5′-CAAGGAAGGCGTAGAGAATGG-3′	158 bp	DQ065757