Nociception is enhanced by the intrathecal injection of 5-methoxy-N,N-dimethyltryptamine in the rat.
The effect of 5-methoxy-N,N-dimethyltryptamine (5-MeODMT) at the spinal cord level on nociceptive reflexes was tested using the tail-flick assay in rats. 5-MeODMT was injected directly into the spinal subarachnoid space of conscious rats via a permanently indwelling intrathecal cannula. Administration of 100 micrograms/rat of 5-MeODMT into the thoracic region, using a 4 cm long cannula, reduced the average percent of control reaction time by 14%. The injection of the same dose of 5-MeODMT into the lumbosacral region, via an 8.6 cm long cannula, decreased the average percent of control reaction time by 25%. The ability of 5-MeODMT to mimic the facilitatory (hyperalgesic) effect on nociception of similar doses of tryptamine, in contrast to the antinociceptive (analgesic) effect of serotonin, suggests an interaction of 5-MeODMT with tryptaminergic rather than serotonergic receptors in the spinal cord.
D000818:Animals; D007276:Injections, Intraventricular; D008297:Male; D008732:Methoxydimethyltryptamines / Q000494:pharmacology*; D009619:Nociceptors / Q000187:drug effects*; D051381:Rats; D011919:Rats, Inbred Strains; D011930:Reaction Time / Q000187:drug effects; D012684:Sensory Thresholds; D012701:Serotonin / Q000031:analogs & derivatives*; D013116:Spinal Cord / Q000187:drug effects*
D008732:Methoxydimethyltryptamines; D012701:Serotonin