5-HT1A Receptors Mediate Analgesia Induced by Emulsified Sevoflurane in Thermal Nociception but Have Little Effect on Chemical Nociception

Pharmacology. 2017;100(1-2):25-30. doi: 10.1159/000464330. Epub 2017 Mar 28.

Abstract

Objective: The study aimed to investigate the relationship between the analgesic effect of sevoflurane and 5-serotonin receptor 1A (5-HT1A R) in the spinal cords of mice.

Methods: Analgesic mouse models were established by intraperitoneal injection of emulsified sevoflurane, and the influence of p-MPPF (a specific antagonist of 5-HT1A Rs) intrathecal injection on the changes in tail-flick latency in tail-withdrawal test, pain threshold in hot-plate test (HPPT), and writhing times in acetic acid-induced writhing test were recorded.

Results: Intraperitoneal injection of emulsified sevoflurane alone produced an analgesic effect (p < 0.05). p-MPPF (2, 4, and 8 μg) alone had no impact on tail-flick latency, HPPT, and writhing times in mice (p > 0.05). The 3 doses of p-MPPF reduced the tail-flick latency or HPPT. p-MPPF 8 μg can increase the writhing times (p < 0.05) in analgesic mice with sevoflurane, while p-MPPF 2 and 4 μg did not affect the writhing times.

Conclusion: 5-HT1A Rs in the spinal cord may be an important target for the analgesic effect of sevoflurane on the thermal nociception, but it has little relation to the anti-chemical chemical nociceptive effect of sevoflurane.

Keywords: 5-HT1A receptor; Analgesia; Sevoflurane.

MeSH terms

  • Aminopyridines / administration & dosage
  • Aminopyridines / pharmacology
  • Analgesics / pharmacology*
  • Animals
  • Disease Models, Animal
  • Dose-Response Relationship, Drug
  • Female
  • Injections, Intraperitoneal
  • Injections, Spinal
  • Male
  • Methyl Ethers / pharmacology*
  • Mice
  • Nociception / drug effects
  • Pain / drug therapy*
  • Pain / pathology
  • Pain Threshold / drug effects
  • Piperazines / administration & dosage
  • Piperazines / pharmacology
  • Receptor, Serotonin, 5-HT1A / drug effects
  • Receptor, Serotonin, 5-HT1A / metabolism*
  • Sevoflurane
  • Spinal Cord / drug effects
  • Spinal Cord / metabolism

Substances

  • Aminopyridines
  • Analgesics
  • Methyl Ethers
  • Piperazines
  • Receptor, Serotonin, 5-HT1A
  • Sevoflurane
  • 4-(2' methoxyphenyl)-1-(2'-(N-(2''-pyridinyl)-4-fluorobenzamido)ethyl)piperazine