The formalin test in rat: validation of an automated system.
A novel, computer-driven, dynamic-force detector was validated for use in measuring the formalin-induced agitation response. Intraplantar administration of formalin (0.25-5%) provoked a biphasic agitation response as measured with the automated system. The magnitude of both phases of the response increased with the intensity of the noxious stimulus. Morphine (1-5 mg/kg, s.c.) inhibited both phase 1 and 2 of the agitation response evoked by 5% formalin with ID50 values of 2.07 +/- 0.47 and 1.35 +/- 0.02 mg/kg, respectively. The non-peptide, NK1 antagonist, (+/-)-CP-96,345 (30 mg/kg, s.c.), partially blocked phase 2 but did not alter the magnitude of phase 1. These results are comparable with those obtained by us and others using a multiple-pain-behavior scoring system or certain uni-dimensional measures. In addition, they indicate that the automated system yields a valid measure of the formalin-induced agitation response.
Jett
M F
MF
Institute of Pharmacology, Syntex Discovery Research, Palo Alto, CA 94304 USA Department of Biomathematics, Syntex Discovery Research, Palo Alto, CA 94304 USA.
Michelson
S
S
D000818:Animals; D001522:Behavior, Animal / Q000187:drug effects; D001713:Biphenyl Compounds / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D005069:Evaluation Studies as Topic; D005528:Foot; D005557:Formaldehyde; D008297:Male; D009020:Morphine / Q000494:pharmacology; D010146:Pain / Q000139:chemically induced* / Q000503:physiopathology*; D010147:Pain Measurement / Q000379:methods*; D051381:Rats; D017207:Rats, Sprague-Dawley; D012815:Signal Processing, Computer-Assisted; D013268:Stimulation, Chemical
D001713:Biphenyl Compounds; D005557:Formaldehyde; D009020:Morphine; C066892:CP 96345