Antinociceptive action of intrathecally administered IGF-I and the expression of its receptor in rat spinal cord

Brain Res. 1996 Oct 21;737(1-2):292-4. doi: 10.1016/0006-8993(96)00747-0.


mRNA transcripts for insulin-like growth factor I (IGF-I) and its receptor are expressed in the lumbar region of the spinal cord. Accordingly, we examined the involvement of IGF-I in nociceptive transmission. An intrathecal injection of IGF-I (200-1000 ng) produced a dose-dependent elevation in nociceptive threshold as indicated by tail flick/withdrawal latency. In contrast, comparable doses of insulin had no significant effect. The time-response curve (15-75 min) revealed that the peak for IGF-I's antinociceptive effect is attained at 30 min. Our data provide evidence that the IGF-I system within the spinal cord may serve as a target for novel analgesics.

MeSH terms

  • Animals
  • Dose-Response Relationship, Drug
  • Female
  • Injections, Spinal
  • Insulin-Like Growth Factor I / pharmacology*
  • Male
  • Nociceptors / drug effects*
  • Polymerase Chain Reaction
  • RNA, Messenger / analysis
  • Rats
  • Rats, Sprague-Dawley
  • Receptor, IGF Type 1 / genetics*
  • Sensory Thresholds / drug effects
  • Sex Factors
  • Spinal Cord / chemistry*
  • Time Factors


  • RNA, Messenger
  • Insulin-Like Growth Factor I
  • Receptor, IGF Type 1