Evaluation of equine electroretinographic responses by using two different electrodes and four different Alpha-2 agonist sedatives

Abstract

ABSTRACT. Rosa M., Botteon P.T.L., Pereira J.S., Brooks D.E. & Rosa M.V.D. Evaluation of equine electroretinographic responses by using two different electrodes and four different Alpha-2 agonist sedatives. [Avaliação da resposta eletroretinográfica de equinos utilizando dois tipos de eletrodos quatro sedativos Alfa-2 agonistas diferentes.] Revista Brasileira de Medicina Veterinária, 36(4):367-374, 2014. Centro de Pesquisa em Oftalmologia Veterinária (CEPOV), Avenida das Américas, 700, Bloco 8, Loja 103J, Barra da Tijuca, Rio de Janeiro, RJ 22640-100, Brasil. E-mail: [email protected] The aim of this study was the evaluation and comparison of field electroretinographic responses in standing horses using two different active electrodes (DTL- plus™ and ERG-jet®), and four different alpha-2 agonist drugs Xylazine, Romifidine, Detomidine, Medetomidine. Forty healthy horses were evaluated by full field ERG. Horses were randomly allocated into eight groups according four sedative drugs and two electrodes types. In all groups a- and b- wave amplitudes and implicit times were investigated and compared for both eyes. Quality and costs of sedation drugs were estimated. This research leaded to the conclusion that there were no significant differences of a- and b-wave complex results between ERG-jet® and DTL-plus™ electrodes with any sedative type. The ERG-jet® lens proved to be more practical during the examination than the DTL-plus™ electrode. The use of a single dose of xylazine, romifidine, detomidine or medetomidine was sufficient to provide a good level of sedation and muscle relaxation during the ERG examination, although detomidine and medetomidine gave slightly superior results when compared with the otherdrugs in this study. The sedation with xylazine was the least when compared with the other drugs and it was also the cheapest to use. Any of the sedatives and either active electrode tested in this study should permit a good full field ERG evaluation in standing horses.