Urinary neurotransmitter patterns are altered in canine epilepsy

   Epilepsy is the most common chronic neurological disease in humans and dogs. Epilepsy is thought to be caused by an imbalance of excitatory and inhibitory neurotransmission. The primary pathway of neurotransmitter elimination is via the urine. In human medicine, non-invasive urinary neurotransmitter analysis is used for the management of medical conditions such as depression and attention-deficit hyperactivity disorder, but not as yet for epilepsy.

   The aim of the current study was to investigate if urinary neurotransmitter profiles differ between dogs with epilepsy and controls. A total of 223 urine samples were analysed from 63 dogs diagnosed with idiopathic epilepsy (IE) and 127 healthy control dogs without epilepsy. The quantification of seven urinary neurotransmitters was performed utilising High-performance liquid chromatography Triple Quadrupole MS/MS technology.

   A significant difference between urinary neurotransmitter levels (glycine, serotonin, norepinephrine/epinephrine ratio, gamma-aminobutyrate/glutamate ratio) of dogs suffering from IE and the control group was found, when sex and neutering status were accounted for.

   The results of this study indicate that the imbalances in the neurotransmitter system which causes epileptic seizures may lead to altered neurotransmitter elimination in the urine of affected dogs and may serve as biomarkers for diagnostics and treatment monitoring. More research on this topic needs to be undertaken to better understand the association of neurotransmitter deviations in the brain and their association with urine neurotransmitter concentrations in dogs with IE.