Opioid involvement in TRH-induced antinociception in the rat following intracerebral administration

Pain. 1989 Aug;38(2):193-201. doi: 10.1016/0304-3959(89)90238-8.


Thyrotropin-releasing hormone (TRH) has an antinociceptive action in the rat. Antinociception was observed using a thermal stimulus (tail-flick test) after TRH administration into lateral ventricle, nucleus raphe magnus, nucleus reticularis paragigantocellularis and amygdaloid nuclei. This effect was short-lived since it was completely abolished 60 min after intracerebroventricular administration. TRH may interact with the opioid systems as its antinociceptive effect was blocked by pretreatment with naloxone.

MeSH terms

  • Analgesics / pharmacology*
  • Animals
  • Brain / drug effects
  • Brain / physiopathology*
  • Endorphins / metabolism
  • Endorphins / physiology*
  • Injections, Intraventricular
  • Male
  • Naloxone / pharmacology*
  • Nociceptors / drug effects*
  • Rats
  • Thyrotropin-Releasing Hormone / pharmacology*


  • Analgesics
  • Endorphins
  • Naloxone
  • Thyrotropin-Releasing Hormone