1. Department of Veterinary Pharmacology, Joint Faculty of Veterinary Medicine, Kagoshima University, 1-21-24 Korimoto, Kagoshima 890-0065, Japan
2. Present address: Assay Division I, National Veterinary Assay Laboratory, Ministry of Agriculture, Forestry and Fisheries, 1-15-1 Tokura, Kokubunji, Tokyo 185-8511, Japan
3. Department of Veterinary Pharmacology, Faculty of Animal Husbandry and Veterinary Medicine, Thai Nguyen University of Agriculture and Forestry, Group 10, Quyet Thang Commune, Thai Nguyen City, Thai Nguyen, Vietnam