Mansour A, et al. (Brain Res. 1995) examined the receptor binding affinities of the POMC, ProEnk and ProDyn peptides to the cloned mu, delta and kappa receptors expressed transiently in transfected COS-1 cells and found that the cloned mu, delta and kappa receptors have high affinity to their endogenous ligands.

Primary structure and functional expression of a guinea pig kappa opioid (dynorphin) receptor. Proc Natl Acad Sci U S A. 1994 .

Primary structure and functional expression of a guinea pig kappa opioid (dynorphin) receptor. Proc Natl Acad Sci U S A. 1994 .

Primary structure and functional expression of a guinea pig kappa opioid (dynorphin) receptor. Proc Natl Acad Sci U S A. 1994 .

Primary structure and functional expression of a guinea pig kappa opioid (dynorphin) receptor. Proc Natl Acad Sci U S A. 1994 .

Primary structure and functional expression of a guinea pig kappa opioid (dynorphin) receptor. Proc Natl Acad Sci U S A. 1994 .