Low-Level Laser Therapy for Osteoarthritis Treatment in Dogs at Missouri Veterinary Practice.

A qualitative survey was electronically distributed to practicing veterinarians in the state of Missouri to evaluate the frequency of use and economic impact of low-level laser therapy (LLLT) for the treatment of osteoarthritis (OA) in dogs in Missouri. The survey response rate was 10% (89/867). Approximately half (43%) of respondents had LLLT units, of which all used LLLT for OA treatment in dogs. In respondents without LLLT units, 20% referred patients for LLLT OA treatment. Training was most often obtained in-house by a representative of the LLLT unit manufacturer (76%). Treatment dose was largely unknown and chosen by predetermined settings on the LLLT unit (65%). In the majority of patients (84%), no treatment site preparation was performed. An average of four patients with OA were treated per wk with an average cost per treated joint of $28 (range: $15-45). This study provides insight into the current clinical use and estimated annual economic impact ($6.2 million per year) of treating a single OA joint in dogs with LLLT by Missouri veterinarians. The frequency with which LLLT is used in the treatment of OA combined with the variation in training and treatment protocols supports the need for further research regarding the application and efficacy of LLLT in dogs with OA.

5-hydroxytryptamine 2C receptors tonically augment synaptic currents in the nucleus tractus solitarii.

The nucleus tractus solitarii (nTS) is the primary termination and integration point for visceral afferents in the brain stem. Afferent glutamate release and its efficacy on postsynaptic activity within this nucleus are modulated by additional neuromodulators and transmitters, including serotonin (5-HT) acting through its receptors. The 5-HT(2) receptors in the medulla modulate the cardiorespiratory system and autonomic reflexes, but the distribution of the 5-HT(2C) receptor and the role of these receptors during synaptic transmission in the nTS remain largely unknown. In the present study, we examined the distribution of 5-HT(2C) receptors in the nTS and their role in modulating excitatory postsynaptic currents (EPSCs) in monosynaptic nTS neurons in the horizontal brain stem slice. Real-time RT-PCR and immunohistochemistry identified 5-HT(2C) receptor message and protein in the nTS and suggested postsynaptic localization. In nTS neurons innervated by general visceral afferents, 5-HT(2C) receptor activation increased solitary tract (TS)-EPSC amplitude and input resistance and depolarized membrane potential. Conversely, 5-HT(2C) receptor blockade reduced TS-EPSC and miniature EPSC amplitude, as well as input resistance, and hyperpolarized membrane potential. Synaptic parameters in nTS neurons that receive sensory input from carotid body chemoafferents were also attenuated by 5-HT(2C) receptor blockade. Taken together, these data suggest that 5-HT(2C) receptors in the nTS are located postsynaptically and augment excitatory neurotransmission.