Comparison of serum brain-derived neurotrophic factor (BDNF) in dogs with and without separation anxiety

Abstract Separation anxiety is a common behavior disorder, but our understanding of its etiology and underlying neurochemical mechanisms remains limited. The purpose of this study was to compare serum brain-derived neurotrophic factor (BDNF) levels in dogs with and without separation anxiety. BDNF, one of several neurotrophins, is prevalent in the limbic region and prefrontal cortex, which are key areas related to the regulation of mood, emotion and cognition. While an enriched environment increases BDNF, stress and glucocorticoid exposure decrease the expression of BDNF in the hippocampus and prefrontal cortex. As separation anxiety is associated with chronic stress, we hypothesized that BDNF levels in dogs affected by separation anxiety would be lower than BDNF levels in non-affected dogs. A total of forty-eight dogs were classified by a board-certified behaviorist as affected (n=15) or non-affected (n=33) by separation anxiety based on review of video clips of the dogs when left alone and owner reports of the dogs’ behavior. Groups did not differ in regard to age, body weight, body condition score, or sex, and the majority of dogs were mixed breed. Fasted serum samples were analyzed with a canine BDNF ELISA. Nine (60%) dogs in the affected group and 12 (36%) dogs in the non-affected group had a BDNF level