Antinociceptive effect of amitraz in mice and rats.
Amitraz, a formamidine insecticide and acaricide used in veterinary practice, presents side effects related to its pharmacological activity on alpha 2-adrenergic receptors. The present study was undertaken to investigate the antinociceptive effect of amitraz in rats and mice. The tail-flick test was used to determine the duration of the antinociceptive effect of the intraperitoneal (ip) administration of amitraz (1 and 2 mg/kg, 10 animals per group) in male Wistar rats weighing 180-220 g. The writhing test (using 10 ml/kg of a 0.6% acetic acid solution as a painful stimulus) was performed in 140 male Swiss mice weighing 20-30 g, divided into 14 groups that received ip injections of saline, amitraz (0.5, 1.0, 1.5, 2.0 and 4.0 mg/kg), xylazine or detomidine (1.0, 1.5, 2.0 and 4.0 mg/kg), in order to compare the effect of amitraz to that caused by xylazine and detomidine, and to investigate the participation of alpha 2-adrenergic receptors which were blocked by idazoxan (1 mg/kg). Amitraz induced a significant antinociceptive effect in both rats and mice. This effect is blocked in mice by idazoxan.
Queiroz-Neto
A
A
Departamento de Morfologia e Fisiologia Animal, Faculdade de Ciências Agrárias e Veterinárias de Jaboticabal, UNESP, SP, Brasil.
Juang
S J
SJ
Souza
K R
KR
Akamatsu
A
A
D000698:Analgesia; D000704:Analysis of Variance; D000818:Animals; D007274:Injections, Intraperitoneal; D007306:Insecticides / Q000494:pharmacology*; D008297:Male; D051379:Mice; D051381:Rats; D017208:Rats, Wistar; D013997:Time Factors; D014052:Toluidines / Q000494:pharmacology*
D007306:Insecticides; D014052:Toluidines; C014983:amitraz