Background: Accelerated repetitive Transcranial Magnetic Stimulation (arTMS) is an emerging modality in both human and veterinary medicine. While previous studies have demonstrated brain changes and behavioral improvements in healthy and patient dogs, the effects of arTMS on neurotransmitter level remains poorly understood. Methods: This study examined the impact of accelerated high-frequency rTMS (aHF-rTMS) on cerebrospinal fluid (CSF) metabolites, focusing on dopaminergic (DOPAC, HVA) and serotonergic (5-HIAA) markers, in healthy dogs and dogs with anxiety-related disorders. A total of 79 dogs were included, consisting of 59 healthy controls and 20 anxious patients. Results: Using generalized linear mixed-effects models, our results revealed a significant group effect, with patient dogs consistently showing lower baseline levels of all three metabolites (DOPAC, HVA, and 5-HIAA) compared to healthy control dogs, supporting a neurochemical basis for anxiety in dogs. Furthermore, arTMS primarily influenced CSF metabolites after just one day of active stimulation, compared to sham or four days of stimulation. Discussion: These results suggests that a shorter duration may have a more immediate impact, with prolonged treatment possibly leading to homeostatic adjustments in the brain. These findings show that arTMS affects neurotransmitter pathways in a time-dependent manner but also highlight the importance of baseline neurochemical differences when evaluating treatment outcomes. While preliminary, our results suggest that rTMS has a time-dependent effect on neurotransmitter dynamics in dogs and may hold translational value for its potential use in treating anxiety-related disorders in both veterinary and human contexts.
Salden et al. (Wed,) studied this question.