No overall statistically significant difference between the dogs receiving active TT001 (group A, 48.3%) and placebo (group B, 42.6%) was observed, regardless of the protocol tested (protocol 1: group A: 47.4%, group B: 41.0%; protocol 2: group A: 50.0%, group B: 45.5%).<h4>Clinical significance</h4>Administration of metabotropic glutamate receptor 5 antagonist TT001 as a single intravenous bolus injection before or after pre-anaesthetic drugs has limited effect on the incidence of gastroesophageal reflux in anaesthetised dogs. Here, GRM5 is linked to gastroesophageal reflux disease.