Antinociceptive properties of intrathecal dexmedetomidine in rats.
Dexmedetomidine is a highly selective alpha 2-adrenoceptor agonist. In this study, the intrathecal administration of dexmedetomidine into the rat lumbar subarachnoid space produced dose-dependent, prolonged antinociception as measured by hot plate and tail flick testing. Intrathecal administration of 3 or 10 micrograms of dexmedetomidine increased hot plate and tail flick latencies to cutoff values within 15 min of injection. Animals receiving 1 microgram of intrathecal dexmedetomidine did not show any significant antinociception when compared to saline controls. The intrathecal administration of the alpha 2-adrenoceptor antagonist, idazoxan, ablated all measurable antinociception produced by the prior injection of 10 micrograms of dexmedetomidine.
Fisher
B
B
Department of Anesthesiology, University of California, San Diego, La Jolla 92093.
Zornow
M H
MH
Yaksh
T L
TL
Peterson
B M
BM
D000316:Adrenergic alpha-Agonists / Q000008:administration & dosage / Q000494:pharmacology*; D000317:Adrenergic alpha-Antagonists; D000700:Analgesics; D000818:Animals; D004146:Dioxanes / Q000494:pharmacology; D019329:Idazoxan; D007093:Imidazoles / Q000008:administration & dosage / Q000037:antagonists & inhibitors / Q000494:pharmacology*; D007278:Injections, Spinal; D008297:Male; D020926:Medetomidine; D051381:Rats; D011919:Rats, Inbred Strains
D000316:Adrenergic alpha-Agonists; D000317:Adrenergic alpha-Antagonists; D000700:Analgesics; D004146:Dioxanes; D007093:Imidazoles; D020926:Medetomidine; D019329:Idazoxan