Neuropathic Pain: The Paradox of Dynorphin

TABLE 1.

K_i Values for Dynorphin Variants with Respect to Human Opioid Receptors

Variant	hKOR^a	K_i (nM) hDOR	hMOR
^a KOR, kappa opioid receptor; DOR delta opioid receptor; MOR, mu opioid receptor.
^b Values represent the mean from two independent experiments. The values regarding the KOR were determined with 1.8 nM [³H]U69,593 (K_d=1.4 nM); those regarding the DOR were determined with 1.5 nM [³H]pCl-DPDPE (K_d=1.3 nM); and those regarding the MOR were determined with 0.45 nM [³H]DAMGO (K_d=0.37 nM).
Dynorphin A	5.3^b	182	6.9
Y-G-G-F-L-R-R-I-R-P-K-L-K-W-D-N-Q
Dynorphin A (1-13)	6.4	141	16.4
Y-G-G-F-L-R-R-I-R-P-K-L-K
Dynorphin A (2-17)	>10,000	>10,000	>10,000
G-G-F-L-R-R-I-R-P-K-L-K-W-D-N-Q
Dynorphin A (2-13)	>10,000	>10,000	>10,000
G-G-F-L-R-R-I-R-P-K-L-K