Nociception is enhanced by the intrathecal injection of 5-methoxy-N,N-dimethyltryptamine in the rat.

Injecting 100 micrograms of 5-MeODMT into the spinal subarachnoid space of conscious rats reduced nociceptive reflex reaction times, indicating a hyperalgesic effect. Administration into the thoracic region decreased the average percent of control reaction time by 14%, while injection into the lumbosacral region produced a 25% decrease. This facilitatory effect on pain perception mimics tryptamine rather than serotonin, suggesting 5-MeODMT interacts with tryptaminergic receptors in the spinal cord.

Study at a glance

Abstract

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.