Effects of supraspinal administration of PG-SPI and PG-KII, two amphibian tachykinin peptides, on nociception in the rat

Peptides. 2000 Nov;21(11):1611-6. doi: 10.1016/s0196-9781(00)00292-8.

Abstract

We investigated and compared the effects of two amphibian tachykinins, the NK1 receptor agonist PG-SPI and the NK3 receptor agonist PG-KII, and the mammalian tachykinins substance P, neurokinin A and neurokinin B on the reaction time to a painful radiant heat stimulus (tail-flick test in rats) after intracerebroventricular injection. PG-SPI (1, 10 and 20 microg) and PG-KII (1, 5 and 10 microg) significantly increased the reaction time. Substance P (10 microg) injected intracerebroventricularly induced antinociception, whereas neurokinin A and neurokinin B did not. Like analgesia evoked by exogenous substance P, PG-SPI-evoked analgesia was blocked by pretreatment with naloxone. Naloxone left PG-KII antinociception unchanged, but the NK3 receptor selective antagonist markedly reduced it. These findings suggest NK1 and NK3 tachykinin receptor system involvement in supraspinal analgesia in rats.

MeSH terms

  • Analgesia
  • Animals
  • Dose-Response Relationship, Drug
  • Hot Temperature
  • Indoles / pharmacology
  • Male
  • Naloxone / pharmacology
  • Narcotic Antagonists / pharmacology
  • Neurokinin A / pharmacology
  • Neurokinin B / pharmacology
  • Neurokinin-1 Receptor Antagonists
  • Oligopeptides / administration & dosage
  • Oligopeptides / pharmacology*
  • Pain Measurement
  • Pain Threshold
  • Piperidines / pharmacology
  • Pyrrolidonecarboxylic Acid / analogs & derivatives
  • Quinuclidines / pharmacology
  • Rats
  • Rats, Wistar
  • Receptors, Neurokinin-1 / agonists
  • Receptors, Neurokinin-3 / agonists
  • Receptors, Neurokinin-3 / antagonists & inhibitors
  • Substance P / pharmacology
  • Tachykinins / administration & dosage
  • Tachykinins / pharmacology*
  • Time Factors

Substances

  • Indoles
  • Narcotic Antagonists
  • Neurokinin-1 Receptor Antagonists
  • Oligopeptides
  • PG-KII peptide
  • Piperidines
  • Quinuclidines
  • R 486
  • R 820
  • Receptors, Neurokinin-1
  • Receptors, Neurokinin-3
  • Tachykinins
  • pyroglutamyl-prolyl-asparaginyl-prolyl-aspartyl-glutamyl-phenylalanyl-phenylalanyl-glycyl-leucyl-methioninamide
  • SR 140333
  • Substance P
  • Naloxone
  • Neurokinin A
  • Neurokinin B
  • Pyrrolidonecarboxylic Acid