Please cite the main reference and the reference for the page that you are using.
oprm_human,
ssr2_human,
ssr5_human,
ssr1_human,
ssr4_human,
ssr3_human,
oprd_human,
oprk_human,
acm1_human,
drd2_human,
5ht4r_human
Methylnaltrexone,
Naloxone,
Chembl2079626,
Lanreotide,
Octreotide,
Metoclopramide