Spinal transection increases the potency of clonidine on the tail-flick and hindlimb flexion reflexes.
The effect of intrathecal clonidine on thermal nociception and hindlimb flexion was assessed in acute and chronic spinally transected rats. After an acute, 1-day spinalization, there was no change in the antinociceptive dose-response function to clonidine, relative to intact rats. However, there was a significant increase in potency 31 days after spinalization. Low doses of clonidine (0.25, 1, 4 and 20 microg) did not affect the nonnociceptive flexion reflex of acute spinal rats, but they elicited a dose-dependent response in chronic spinal rats. These data provide behavioral evidence of supersensitivity to alpha-adrenoceptor agonists in chronic spinal rats.
Advokat
Claire
C
Department of Psychology, 236 Audubon Hall, Louisiana State University, Baton Rouge, LA 70803, USA. cadvoka@lsu.edu
D000316:Adrenergic alpha-Agonists / Q000494:pharmacology*; D000818:Animals; D003000:Clonidine / Q000494:pharmacology*; D003655:Decerebrate State; D004305:Dose-Response Relationship, Drug; D006614:Hindlimb / Q000294:innervation; D008297:Male; D051381:Rats; D017207:Rats, Sprague-Dawley; D012018:Reflex / Q000187:drug effects* / Q000502:physiology; D013119:Spinal Cord Injuries / Q000503:physiopathology*; D013623:Tail / Q000294:innervation
D000316:Adrenergic alpha-Agonists; D003000:Clonidine