Dynorphin A(6-12) analogs suppress thermal edema.
Dynorphin A (Dyn A) is a 17-residue opioid peptide derived from prodynorphin precursors found in mammalian tissues. Removal of Tyr1 from Dyn A produces a peptide that is more potent than Dyn A in attenuating the acute phase of the inflammatory response, as measured by inhibition of heat-induced edema in the anesthetized rat's paw (exposure to 58 degrees C water for 1 min). Dyn A(2-17), however, no longer interacts with opioid receptors. It was postulated that the non-opioid anti-inflammatory actions of Dyn A(2-17) may reside in Dyn A(6-12); that is, Arg-Arg-Ile-Arg-Pro-Lys-Leu. here we report on the activities of Dyn A(6-12) analogs modified by substitutions on the N terminus, by single N-methyl substitution and by single replacement of residues by alanine. The results indicated that the minimal sequence required for an anti-edema ED50 of <1.0 micromol/kg i.v. was anisoyl-Arg6-Arg7-Xaa8-Arg9-Pro10)-Xaa11-+ ++Xaa12-NH2. A prototype, p-anisoyl-[D-Leu12] Dyn A(6-12)-NH2, with an ED50 of 0.20 micromol/kg i.v. compared to an ED50 of 0.08 micromol/kg i.v. for Dyn A(2-17), was selected for further tests of biological activity. This analog, like Dyn A(2-17), lowered blood pressure in anesthetized rats. In a model of neurogenic inflammation, produced by antidromic stimulation of the vagus in the anesthetized rat, p-anisoyl-[D-Leu12] Dyn A(6-12)-NH2, 0.23 micromol/kg i.v., attenuated the negativity of tracheal tissue interstitial pressure (Pif), which normally develops after nerve stimulation. Modulation of interstitial pressure may be the mechanistic basis for the anti-edema properties of these Dyn A(6-12) analogs.
Wei
E T
ET
School of Public Health, University of California, Berkeley 94720, USA.
Thomas
H A
HA
Gjerde
E A
EA
Reed
R K
RK
Burov
S V
SV
Korolkov
V I
VI
Glynskaya
O V
OV
Dorosh
M Y
MY
Vlasov
G P
GP
D000818:Animals; D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000737:chemistry / Q000494:pharmacology*; D004399:Dynorphins / Q000737:chemistry / Q000494:pharmacology*; D004487:Edema / Q000188:drug therapy; D006614:Hindlimb / Q000473:pathology; D006358:Hot Temperature; D008297:Male; D010446:Peptide Fragments / Q000737:chemistry / Q000494:pharmacology*; D051381:Rats; D017207:Rats, Sprague-Dawley
D000894:Anti-Inflammatory Agents, Non-Steroidal; D010446:Peptide Fragments; C095267:dynorphin A (6-12); D004399:Dynorphins; C082245:dynorphin (2-17)