Effects of supraspinal administration of PG-SPI and PG-KII, two amphibian tachykinin peptides, on nociception in the rat.
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.
Improta
G
G
Institute of Pharmacology, University "La Sapienza," P.le A. Moro 5, 00185, Rome, Italy. giovannaimprota@uniroma.it
Broccardo
M
M
D000698:Analgesia; D000818:Animals; D004305:Dose-Response Relationship, Drug; D006358:Hot Temperature; D007211:Indoles / Q000494:pharmacology; D008297:Male; D009270:Naloxone / Q000494:pharmacology; D009292:Narcotic Antagonists / Q000494:pharmacology; D015288:Neurokinin A / Q000494:pharmacology; D015287:Neurokinin B / Q000494:pharmacology; D064729:Neurokinin-1 Receptor Antagonists; D009842:Oligopeptides / Q000008:administration & dosage / Q000494:pharmacology*; D010147:Pain Measurement; D017288:Pain Threshold; D010880:Piperidines / Q000494:pharmacology; D011761:Pyrrolidonecarboxylic Acid / Q000031:analogs & derivatives; D011812:Quinuclidines / Q000494:pharmacology; D051381:Rats; D017208:Rats, Wistar; D018040:Receptors, Neurokinin-1 / Q000819:agonists; D018042:Receptors, Neurokinin-3 / Q000819:agonists / Q000037:antagonists & inhibitors; D013373:Substance P / Q000494:pharmacology; D015320:Tachykinins / Q000008:administration & dosage / Q000494:pharmacology*; D013997:Time Factors
D007211:Indoles; D009292:Narcotic Antagonists; D064729:Neurokinin-1 Receptor Antagonists; D009842:Oligopeptides; C103114:PG-KII peptide; D010880:Piperidines; D011812:Quinuclidines; C109442:R 486; C109443:R 820; D018040:Receptors, Neurokinin-1; D018042:Receptors, Neurokinin-3; D015320:Tachykinins; C096302:pyroglutamyl-prolyl-asparaginyl-prolyl-aspartyl-glutamyl-phenylalanyl-phenylalanyl-glycyl-leucyl-methioninamide; C085215:SR 140333; D013373:Substance P; D009270:Naloxone; D015288:Neurokinin A; D015287:Neurokinin B; D011761:Pyrrolidonecarboxylic Acid