[Analgesic action of sodium diclofenac: behavioral and electrophysiological study in normal and polyarthritic rats].
In a behavioural study, the effects of intravenous diclofenac in a range of doses were determined by measuring vocalization thresholds to paw pressure in normal and Freund's adjuvant-induced arthritic rats. In normal rats, 6 and 9 mg/kg diclofenac produced an increase in vocalization thresholds (mean threshold values were respectively 135.67 +/- 3.30 per cent and 157.41 +/- 4.62 per cent of the control at 30 min; n = 9 for each group), no effect resulting with 3 mg/kg. In arthritic rats, 3, 6 and 9 mg/kg diclofenac induced a clear analgesic effect (mean threshold values being 172.22 +/- 4.26 per cent, 201.76 +/- 4.76 per cent and 222.33 +/- 5.10 per cent respectively of the control at 25 min, n = 9 for each group), no effect being observed with 1.5 mg/kg. An electrophysiological study performed on arthritic rats considered the effect of 6 mg/kg diclofenac upon the neuronal ventrobasal thalamic responses induced by mode-rate stimulation of an inflamed joint. The responses were depressed by about 50 per cent, 20 minutes after the injection. These results show that diclofenac displays a direct effect on pain processing; this effect is more potent in arthritic rats than in normal rats.
Attal
N
N
Unité de Recherches de Physiopharmacologie du système nerveux central de l'INSERM (U161), Paris.
Guilbaud
G
G
D000818:Animals; D001168:Arthritis / Q000188:drug therapy* / Q000503:physiopathology; D001522:Behavior, Animal / Q000187:drug effects*; D004008:Diclofenac / Q000494:pharmacology*; D004195:Disease Models, Animal; D004305:Dose-Response Relationship, Drug; D004594:Electrophysiology; D051381:Rats; D011919:Rats, Inbred Strains; D014828:Vocalization, Animal
D004008:Diclofenac
Action analgésique du sel de sodium du diclofénac: étude comportementale et électrophysiologique, réalisée chez le rat normal et chez le rat polyarthritique.