Vagal nerve stimulation blocks interleukin 6-dependent synaptic hyperexcitability induced by lipopolysaccharide-induced acute stress in the rodent prefrontal cortex.
The ratio between synaptic inhibition and excitation (sI/E) is a critical factor in the pathophysiology of neuropsychiatric disease.
We recently described a stress-induced interleukin-6 dependent mechanism leading to a decrease in sI/E in the rodent temporal cortex. The aim of the present study was to determine whether a similar mechanism takes place in the prefrontal cortex, and to elaborate strategies to prevent or attenuate it.
We used aseptic inflammation (single acute injections of lipopolysaccharide, LPS, 10mg/kg) as stress model, and patch-clamp recording on a prefrontal cortical slice preparation from wild-type rat and mice, as well as from transgenic mice in which the inhibitor of IL-6 trans-signaling sgp130Fc was produced in a brain-specific fashion (sgp130Fc mice).
The anti-inflammatory reflex was activated either by vagal nerve stimulation or peripheral administration of the nicotinic α7 receptor agonist PHA543613.
We found that the IL-6-dependent reduction in prefrontal cortex synaptic inhibition was blocked in sgp130Fc mice, or – in wild-type animals – upon application sgp130Fc.
Similar results were obtained by activating the “anti-inflammatory reflex” – a neural circuit regulating peripheral immune response – by stimulation of the vagal nerve or through peripheral administration of the α7 nicotinic receptor agonist PHA543613.
Our results indicate that the prefrontal cortex is an important potential target of IL-6 mediated trans-signaling, and suggest a potential new avenue in the treatment of a large class of hyperexcitable neuropsychiatric conditions, including epilepsy, schizophrenic psychoses, anxiety disorders, autism spectrum disorders, and depression.
Copyright © 2014. Published by Elsevier Inc.
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