ALS	Amyotrophic Lateral Sclerosis
β-End 1–31	β-endorphin 1–31
BD1047	N′-[2-(3,4-dichlorophenyl)ethyl]-N,N,N′-trimethylethane-1,2-diamine;dihydrobromide
BD1063	1-[2-(3,4-dichlorophenyl)ethyl]-4-methylpiperazine
BiP	78-kDa glucose-regulated binding protein (GRP78)
CCI	Unilateral sciatic nerve chronic contrition injury
CHO	Chinese hamster ovarian cells
CNS	Central nervous system
DADLE	([D-Ala2, D-Leu5]-Enkephalin
D-Ala2 Deltorphin II	Tyr-D-Ala-Phe-Glu-Val-Val-Gly amide
DAMGO	([D-Ala2, N-MePhe4, Gly-ol]-enkephalin
DOR	Delta-opioid receptor
DPDPE	([D-Pen2,D-Pen5]enkephalin)
ε	Epsilon receptor
EC50	Efficacious concentration to reduce 50% a given effect
ER	Endoplasmic reticulum
HINT1	Histidine triad nucleotide binding protein 1
GPCR	G-protein-coupled receptor
Icv	Intracerebroventricular
KOR	Kappa-opioid receptor
MOR	Mu-opioid receptor
αN-acetyl	Acetylated β-End N terminal Y1, α position
NMDA	N-methyl-d-aspartate acid
NMDAR	N-methyl-d-aspartate acid glutamate receptor
PAG	Periaqueductal grey matter
pMCAO	Permanent unilateral middle cerebral artery occlusion
POMC	Proopiomelanocortin
(+/−)PPCC	(1R,2S/1S,2R)-2-[4-hydroxy-4-phenylpiperidin-1-yl)methyl]-1-(4-methylphenyl) cyclopropanecarboxylate
PRE084	2-(4-morpholinethyl)-1-phenylcyclohexanecarboxylate hydrochloride
PTX	Pertussis toxin
RVD	Rat vas deferens
σ1R	Type 1 sigma receptor
σ2R	Type 2 sigma receptor
SBM	Solubilized brain membranes enriched in synaptosomes
SKF-10,047	(2S,6S,11S)-3-Allyl-1,2,3,4,5,6-hexahydro-6,11-dimethyl-2,6-methano-3-benzazocine-8-ol
U-50,488H	Trans-3,4-Dichloro-N-methyl-N-[2-(1-pyrrolidinyl)cyclohexyl]-benzeneacetamide
WT	Wild-type