%Ees+ct	Percentage share of polar character of interaction according to PIEDA analysis
%MPE	Percent of the maximal possible effect
ACN	Acetonitrile
AUC	Area under the curve
CCK	Cholecystokinin
DALDA	[d-Arg2, Lys4]-Dermorphin-(1-4)-amide
DAMGO	[d-Ala2, N-Me-Phe4, Gly5-ol]-Enkephalin
DCC	N,N′-dicyclohexylcarbodiimide
DCU	N,N′-dicyclohexylourea
Dmt	2′,6′-Dimethyl-l-tyrosine
DMF	Dimethylformamide
DOR	δ-Opioid receptor
Ect	Change-transfer contribution to PIE
Edisp	Dispersion contribution to PIE
Eex	Exchange repulsion contribution to PIE
Ees	Electrostatic contribution to PIE
ESI-MS	Electrospray-ionization mass spectrometry
Esolv	Gibbs solution energy
FA	Formic acid
FMO	Fragment molecular orbital
GAMESS	General Atomic and Molecular Electronic Structure System
GTPγS	Guanosine 5′-O-[γ-thio]triphosphate
HOSu	N-Hydroxysuccinimide
HPLC	High performance liquid chromatography
IC50	Half-maximal inhibitory concentration
Ki	Inhibition constant
Ki-67	Ki-67 protein
MD	Molecular dynamics
MEM	Minimal Essential Medium
MF	Morphine
MOR	μ-Opioid receptor
MTT	3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide
NK1R	Neurokinin-1 receptor
OPM	Orientation of Proteins in Membrane Database
PIE	Pair interaction energy
PIEDA	Pair interaction energy decomposition analysis
POPC	Phosphatidylcholine
R	Correlation coefficient
RMSD	Root mean square deviation
RP-HPLC	Reversed-phase high performance liquid chromatography
SP	Substance P
TFA	Trifluoroacetic acid
TLC	Thin layer chromatography
TM	Transmembrane helix
TMG	1,1,3,3-Tetramethylguanidine
VGCC	Voltage gated calcium channel