Test-dependent antinociceptive effect of spinal serotonin release induced by intrathecal p-chloroamphetamine in mice.
The effect of direct intrathecal injection of p-chloroamphetamine (PCA) into the lumbar subarachnoid space was investigated in mice. PCA (0.6 - 20 micrograms) induced a dose-related prolongation of response latencies in the tail-flick test, but failed to affect the hind-paw lick response in a hot-plate test employing slowly rising temperature. PCA (5 micrograms) given intracerebroventricularly did, however, significantly elevate the response temperature in the hot-plate test. The antinociceptive effect of PCA in the tail-flick test was prevented by spinalization, by pretreatment with the selective serotonergic re-uptake blocker zimelidine (20 mg X kg-1 i.p.) and by the serotonin synthesis inhibitor p-chlorophenylalanine (300 + 300 + 150 mg X kg-1 i.p. 72, 48 and 24 h before test). It is concluded that PCA given intrathecally releases serotonin from spinal terminals, which may under certain conditions induce antinociception.
Berge
O G
OG
Fasmer
O B
OB
Jørgensen
H A
HA
Hole
K
K
D000662:Amphetamines / Q000494:pharmacology*; D000818:Animals; D004305:Dose-Response Relationship, Drug; D007278:Injections, Spinal; D008297:Male; D051379:Mice; D008815:Mice, Inbred Strains; D010146:Pain / Q000503:physiopathology*; D011930:Reaction Time / Q000187:drug effects; D011985:Receptors, Serotonin / Q000187:drug effects; D012701:Serotonin / Q000378:metabolism / Q000502:physiology*; D013116:Spinal Cord / Q000378:metabolism / Q000502:physiology*; D015031:Zimeldine / Q000494:pharmacology; D010133:p-Chloroamphetamine / Q000494:pharmacology*
D000662:Amphetamines; D011985:Receptors, Serotonin; D012701:Serotonin; D015031:Zimeldine; D010133:p-Chloroamphetamine