Antinociceptive action of intrathecally administered IGF-I and the expression of its receptor in rat spinal cord.
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.
Bitar
M S
MS
Department of Pharmacology and Toxicology, Kuwait University, Faculty of Medicine, Safat, Kuwait.
Al-Bustan
M
M
Nehme
C L
CL
Pilcher
C W
CW
D000818:Animals; D004305:Dose-Response Relationship, Drug; D005260:Female; D007278:Injections, Spinal; D007334:Insulin-Like Growth Factor I / Q000494:pharmacology*; D008297:Male; D009619:Nociceptors / Q000187:drug effects*; D016133:Polymerase Chain Reaction; D012333:RNA, Messenger / Q000032:analysis; D051381:Rats; D017207:Rats, Sprague-Dawley; D017526:Receptor, IGF Type 1 / Q000235:genetics*; D012684:Sensory Thresholds / Q000187:drug effects; D012737:Sex Factors; D013116:Spinal Cord / Q000737:chemistry*; D013997:Time Factors
D012333:RNA, Messenger; D007334:Insulin-Like Growth Factor I; D017526:Receptor, IGF Type 1