“…In preclinical settings, specific strains of rats (Lai & Lui, 2000;Weinger et al, 1995), rabbits (Soares et al, 2014), and guinea pigs (Brent & Bot, 1992) developed opioid-induced muscle rigidity and were considered potential translational animal models in relevant research fields. Furthermore, this phenomenon has been reported in other animal species as well, including equids (Knych et al, 2015) and elk (Paterson et al, 2009). Here, we describe the rare case of a Terumo Corporation, Tokyo, Japan) was infused intravenously (5-8 ml kg −1 h −1 ) through the cephalic vein.…”