AF	Annulus fibrosus
AR	Adrenoceptor
cDNA	Complementary desoxy ribonucleic acid
Col II	Type II collagen
Col VI	Type VI collagen
Col XII	Type XII collagen
COMP	Cartilage oligomeric matrix protein
DCN	Decorin
DMEM/F12	Dulbecco’s modified eagle’s medium and Ham’s F-12 Medium
DMMB	1,9-Dimethyl-methylene blue
ECM	Extracellular matrix
ERK	Extracellular signal-regulated kinases
FBS	Fetal bovine serum
GAPDH	Glyceraldehyde-3-phosphate dehydrogenase
HT29	Human colon cancer cell line
IL	Interleukin
IVD	Intervertebral disc
IVDD	Intervertebral disc degeneration
mRNA	Messenger ribonucleic acid
NE	Norepinephrine
NP	Nucleus pulposus
OA	Osteoarthritis
P/S	Penicillin streptomycin
PCR	Polymerase chain reaction
pERK	Phosphorylated extracellular signal-regulated kinases
PKA	Protein kinase A
pPKA	Phosphorylated protein kinase A
RT-PCR	Reverse-transcriptase PCR
Saf-O	Safranin-O/fast green staining
sGAG	Sulphated glycosaminoglycans
TH	Tyrosine hydroxylase
WT	Wildtype mice