Spinal antinociceptive effects of [d-Ala2]deltorphin II, a novel and highly selective delta-opioid receptor agonist

doi:10.1016/0196-9781(92)90017-W

Peptides

Volume 13, Issue 6, November–December 1992, Pages 1123-1126

https://doi.org/10.1016/0196-9781(92)90017-W Get rights and content

Abstract

Pharmacological assays in isolated tissues and binding tests have recently shown that two peptides, with the sequence Tyr-d-Ala-Phe-Asp-(or Glu)-Val-Val-Gly-NH₂, isolated from skin extracts of Phyllomedusa bicolor and named [d-Ala²]deltorphin I and II, respectively, possess a higher affinity and selectivity for delta-opioid receptors than any other known natural compound. Since much evidence supports the role of spinal delta-opioid sites in producing antinociceptive effects, we investigated whether analgesia might be detected by direct spinal cord administration of [d-Ala²]deltorphin II (DADELT II) in the rat. The thermal antinociceptive effects of intrathecal DADELT II and dermorphin, a potent mu-selective agonist, were compared at different postinjection times by means of the tail-flick test. The DADELT II produced a dose-related inhibition of the tail-flick response, which lasted 10–60 min depending on the dose and appeared to be of shorter duration than the analgesia produced in rats after intrathecal injection of dermorphin (20–120 min). The analgesic effect of infused or injected DADELT II was completely abolished by naltrindole, the highly selective delta antagonist. These results confirm the involvement of delta receptors in spinal analgesic activity in the rat.

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ArticleSpinal antinociceptive effects of [d-Ala2]deltorphin II, a novel and highly selective delta-opioid receptor agonist

Abstract

Brain Res.

Trends Pharmacol. Sci.

Eur. J. Pharmacol.

Eur. J. Pharmacol.

Eur. J. Pharmacol.

Peptides

Brain Res.

Brain Res.

Physiol. Behav.

Article
Spinal antinociceptive effects of [d-Ala²]deltorphin II, a novel and highly selective delta-opioid receptor agonist