Cullen L K, Reynoldson J A
School of Veterinary Studies, Murdoch University, Western Australia.
Res Vet Sci. 1990 Mar;48(2):162-4.
Ataxia is an occasional side effect of amitraz when used as a wash to treat dogs with demodectic mange. In the present study, successive doses of 0.5, 2, 5 and 10 mg kg-1 amitraz were given intravenously at intervals of nine minutes to thiopentone/methoxyflurane/oxygen anaesthetised dogs. The amplitude of the evoked muscle action potential to electrical stimulation of the right ulnar nerve and the muscle refractory period were unchanged by increasing doses of amitraz but there was a progressive and significant decrease in nerve conduction velocity. The minimum recorded nerve conduction velocity (50.7 +/- 1.5 m s-1) was still within an adequate range. From these results it appears that the ataxia following amitraz is unlikely to be attributable to peripheral mechanisms. The concurrent amitraz-induced rise in mean arterial pressure and bradycardia was consistent with previous findings in which alpha 2-adrenoceptors were shown to be the major mediators.
当作为洗剂用于治疗犬蠕形螨病时，阿维菌素偶尔会产生共济失调这一侧效应。在本研究中，以9分钟的间隔，向硫喷妥钠/甲氧氟烷/氧气麻醉的犬静脉内依次给予0.5、2、5和10mg/kg的阿维菌素。随着阿维菌素剂量增加，右侧尺神经电刺激诱发的肌肉动作电位幅度和肌肉不应期未发生变化，但神经传导速度出现渐进性显著下降。记录到的最低神经传导速度（50.7±1.5m/s）仍在适当范围内。从这些结果来看，阿维菌素后的共济失调不太可能归因于外周机制。同时，阿维菌素引起的平均动脉压升高和心动过缓与之前的研究结果一致，在之前的研究中，α2肾上腺素受体被证明是主要介质。
