Friday, August 17, 2012

Vagal Nerve Stimulation and Mechanisms for Treating Depression

How does VNS work?

Vagal Nerve Stimulation (VNS) has proven effective in treating severe, intractable depression. It is a procedure that sends electrical impulses into your brain in an effort to improve depression symptoms. Side effects with VNS Therapy include temporary hoarseness or a slight change in voice tone, increased coughing, shortness of breath upon physical exertion, and a tickling in the throat (Rush AJ, Sackeim HA, Marangell LB, et al.).

I wanted to post highlights of a recent study that for the first time shows that VNS increases brain-derived neurotrophic factor (BDNF) in brain or activate, via phosphorylation, its receptor, TrkB: Havan Furmaga, Flavia Regina Carreno, and Alan Frazer. Vagal Nerve Stimulation Rapidly Activates Brain-Derived Neurotrophic Factor Receptor TrkB in Rat Brain. PLoS One. 2012; 7(5): e34844. Published online 2012 May 1. doi: 10.1371/journal.pone.0034844.

Images: Vagal nerve stimulation (VNS) rapidly induces TrkB activation in rat hippocampus. Effects of acute (2 hr) VNS, desipramine (DMI, 10 mg/kg, i.p) or fluoxetine (15 mg/kg, i.p) on TrkB phosphorylation at different tyrosine residues in rat hippocampus.Phospho-TrkB values are normalized against total-TrkB values. One-way MANOVA, Student's Newman-Keuls post-hoc test, *P<0 .05=".05" br="br" group.="group." n="4−8" per="per">

It is this phosphorylation of TrkB that could make VNS a distinct and effective treatment. This VNS induced mechanism is distinct from the effect of standard antidepressant drugs.

Further understanding could result in therapies that are less intrusive, less costly and more effective for treating severe depressive disorders. I will continue to post new findings here.

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