Preemptive effect of intravenous ketamine in the rat: concordance between pain behavior and spinal fos-like immunoreactivity.
BACKGROUND
The purpose of this study was to compare behavioral antinociceptive responses with spinal fos-like immunoreactivity (FLI) for a intravenous ketamine injection between pre vs. postformalin administration in rats.


METHODS
Sprague-Dawley rats (250-300 g) were prepared to receive either saline or ketamine. All rats were randomly divided into three groups: control, pretreatment and post-treatment group. Formalin (5%) 100 microl was injected into the hindpaw. Pain related behavior and FLI in the lumbar spinal cord was examined.


RESULTS
Flinches of phase 2 were 239.3 (22,8), 118.6 (7,5) (P < 0.05 vs. control and post-treatment group), and 186.7 (16,6) in the control, pre and, post-treatment groups, respectively. Fos-like immunoreactivity expression was significantly correlated with phase 2 flinching behavior (P < 0.001).


CONCLUSIONS
Pretreatment with intravenous ketamine inhibits inflammatory pain behavior and FLI expression following a formalin injection in rats, suggesting that pretreatment of ketamine plays an important role in preemptive analgesia.
Lee
I-H
IH
Department of Anesthesiology, Samsung Cheil Hospital, Sungkyunkwan University School of Medicine, Seoul, Korea.
Lee
I-O
IO
D000700:Analgesics / Q000008:administration & dosage / Q000494:pharmacology*; D000704:Analysis of Variance; D000818:Animals; D001522:Behavior, Animal / Q000187:drug effects*; D004195:Disease Models, Animal; D004202:Disinfectants / Q000008:administration & dosage; D005557:Formaldehyde / Q000008:administration & dosage; D007275:Injections, Intravenous; D007649:Ketamine / Q000008:administration & dosage / Q000494:pharmacology*; D008297:Male; D010146:Pain / Q000276:immunology / Q000517:prevention & control*; D016760:Proto-Oncogene Proteins c-fos / Q000187:drug effects* / Q000276:immunology; D051381:Rats; D017207:Rats, Sprague-Dawley; D012965:Sodium Chloride / Q000008:administration & dosage; D013116:Spinal Cord / Q000187:drug effects* / Q000276:immunology; D013997:Time Factors
D000700:Analgesics; D004202:Disinfectants; D016760:Proto-Oncogene Proteins c-fos; D005557:Formaldehyde; D012965:Sodium Chloride; D007649:Ketamine