Intrathecal substance P modulates the depressant effect of 5-methoxy-N,N-dimethyltryptamine on a reflex response to radiant heat in mice.
The effect of intrathecal (i.th.) substance P (SP) on antinociception elicited by the serotonin (5-HT) receptor agonist 5-methoxy-N,N-dimethyltryptamine (5-MeODMT) was investigated in mice by means of the tail-flick method. Substance P (0.07, 0.7 or 7 micrograms) induced a behavioral syndrome for 1-2 min, but had no apparent toxic or neurologic effects and did not alter the tail-flick response to noxious radiant heat 30 min after injection. The depressant effect of 5-MeODMT (3 mg/kg) on tail-flick responses was, however, markedly attenuated when administered 30 min after SP. The tail skin temperatures of vehicle- and SP-injected mice were nearly identical 30 min after i.th. injection as well as after administration of 5-MeODMT. The results indicate a functional interaction between SP and 5-HT in spinal nociceptive processes, and it is suggested that i.th. SP modulates the function of 5-HT receptors.
Eide
P K
PK
Department of Physiology, University of Bergen, Norway.
Hole
K
K
D000818:Animals; D006358:Hot Temperature; D007278:Injections, Spinal; D008297:Male; D008732:Methoxydimethyltryptamines / Q000494:pharmacology*; D051379:Mice; D010146:Pain / Q000503:physiopathology*; D011985:Receptors, Serotonin / Q000187:drug effects / Q000502:physiology*; D012018:Reflex / Q000187:drug effects; D012701:Serotonin / Q000031:analogs & derivatives*; D013373:Substance P / Q000494:pharmacology*; D013623:Tail / Q000294:innervation
D008732:Methoxydimethyltryptamines; D011985:Receptors, Serotonin; D012701:Serotonin; D013373:Substance P