Comparison of the antinociceptive effect between the cyclic dipeptide cyclo (Tyr(Et)-homoarginine) and the linear dipeptide Boc-Tyr(Et)-homoarginine-OMe in rats.

Abstract

Abstract-The antinociceptive effect of the cyclic dipeptide cyclo[Tyr(Et)-homo arginine] (C.TEHA) was examined utilizing the tail flick test and the digitus pinching test in rats in comparison with the linear dipeptide Boc-Tyr(Et)-homoarginine OMe (B.TEHM).Though both dipeptides administered into the lateral, 3rd and 4th cerebroventricles produced antinociceptive effects equipotent to morphine, except for the 4th cerebroventricular administration of B.TEH M, the administration into the spinal subarachnoid space was without effect. The effect of B.TEHM was com pletely antagonized by the pretreatment of naloxone (i.p.) when administered into -ihe 3rd cerebroventricle where its effect was demonstrated to be the most potent .

Dermorphin analogues containing D‐kyotorphin: structure‐antinociceptive relationships in mice

“…Since the isolation and identification of dermorphin in skin extracts of the Brazilian frog (Montecucchi et al, 1981a,b), evidence has accumulated that several other naturally occurring and synthetic peptides have narcotic-like pharmacological activity Broccardo et al, 1981;Sato et al, 1984a;1985). The sequence of dermorphin was determined to be Tyr-D-Ala-Phe-Gly-Tyr-Pro-Ser-NH2 (Montecucchi et al, 1981 a) and it was found to have pronounced opioid antinociceptive activity (Broccardo et al, 1981;Sato et al, 1984b).…”