Antinociceptive activities of synthetic dipeptides in mice

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

“…However, C.TEHA had no effect when administered into the spinal subarachnoid space and was not reversed by naloxone at doses which completely antagonized the antinociceptive effect of morphine. We previously reported that the antinociceptive effect of cyclo(N methyl-L-Tyr-L-Arg) was incompletely re versed by 2 mg/kg or 8 mg/kg of naloxone in the mouse tail pressure test (19,20). In addition, since the effect of C.TEHA was incompletely reversed by high dose of naloxone, it may be certain that C.TEHA induced antinociception is mediated through opioid receptors other than mu receptors or non-opioid receptors.…”

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

“…Antinociceptive activity was measured by the tail-pressure method as previously described (Sakurada et al, 1982 32.8 ± 10.4* 73.7 ± 8.9 10.3 ± 4-3* 83.7 ± 7.8 17.0 ± 4.7* 92.1 ± 5.2 25.1 ± 5.2* 76.8 ± 9.9 44.7 ± 6.6* 43.3 ± 7.3* 11.5 ± 0.8 68.3± 8.0 6.9 ± 5.1* 85.0 ± 9.1 40.9 ± 12.0* 62.5± 7.9 17.8 ± 8.4* 92.5 ± 5.7 19.8 ± 4.6* 81.6± 9.4 18.9 ± 5.6* 59.0 ± 8. N-terminal fragments, hepta-, penta-and tetrapeptides, although the tripeptide still maintained a higher activity than morphine.…”

“…The antinociceptive action produced by intracisternal or intracerebroventricular (i.c.v.) administration of kyotorphin (L-Tyr-L-Arg) can be prolonged by the use of an analogue (L-Tyr-DArg) (Takagi et al, 1979a;Sakurada et al, 1982). The present study was undertaken in order to investigate the effect of substituting D-Arg for D-Ala in position 2 in the peptide chain of dermorphin, and to determine the smallest sequential analogue of dermorphin able to exhibit full activity.…”

Structure‐antinociceptive activity studies with neurotensin

“…Groups of ten mice were used for each experiment. Antinociceptive activities were determined using tail pressure as previ-©) The Macmillan Press Ltd 1984 ously described (Sakurada et al, 1982). The base of the tail was pressed mechanically (10 mmHg s-1) and the level of pressure in mmHg that evoked biting or an aversive response was noted.…”