BBB	blood–brain barrier
13C NMR	C-nuclear magnetic resonance
CHO	Chinese hamster ovary
CI	confidential interval
CPP	conditioned-place preference
DAMGO	H-Tyr-D-Ala-Gly-NMe-Phe-Gly-ol
DMSO	dimethyl sulfoxide
Dmt	2’,6’-dimethyltyrosine
DOR	delta opioid receptor
DPDPE	c[D-Pen2,D-Pen5]encephalin
EC50	concentration for 50% of maximal effect
ED50	dose for 50% of maximal effect
ESI-MS	electron spray ionization mass spectrometry
HBSS	Hank’s balanced salt solution
HCV	hepatitis C virus
1H NMR	H-nuclear magnetic resonance
i.c.v.	intracerebroventricular
i.p.	intraperitoneal
i.v.	intravenous
KOR	kappa opioid receptor
KOR KO	kappa opioid receptor gene-disrupted mice
LC-MS	liquid chromatography coupled to mass spectrometry
LP	1,3-[(2R,6R,11R)-8-hydroxy-6,11-dimethyl-1,4,5,6-tetrahydro-2,6-methano-3-benzazocin-3(2H)-yl]-N-phenylpropanamide
MMP	matrix metalloproteinase
MOR	mu opioid receptor
MOR KO	mu opioid receptor gene-disrupted mice
MRM	multiple reaction monitoring
MS	mass spectrometry
nor-BNI	nor-binaltorphimine
NTPase	Nile virus nucleoside triphosphatases
PBS	phosphate buffered saline
PMSF	phenylmethanesulfonyl fluoride
RP-HPLC	reverse phase high-performance liquid chromatography
s.c.	subcutaneous
TACE	TNF-alpha converting enzyme
TFA	trifluoroacetic acid
UV	ultra violet