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Vagal Stimulation Reduces the Severity of Maximal Electroshock Seizures in Intact Rats: Use of a Cuff Electrode for Stimulating and Recording
Author(s) -
WOODBURY J. WALTER,
WOODBURY DIXON M.
Publication year - 1991
Publication title -
pacing and clinical electrophysiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.686
H-Index - 101
eISSN - 1540-8159
pISSN - 0147-8389
DOI - 10.1111/j.1540-8159.1991.tb04053.x
Subject(s) - medicine , pentylenetetrazol , tonic (physiology) , stimulation , anesthesia , anticonvulsant , cuff , epilepsy , surgery , psychiatry
J. Zabaru showed thai repetitive vagal stimulation (VS) prevents or ameliorates convulsive seizures in dogs. We have studied the effects of VS on maximal electroshock seizures (MES) in intact rats: (1) A 5 wire cuff electrode was developed for stimulating and recording from the vagus. Compound action potentials (AP) were recorded and strength‐duration curves obtained for A and C fibers. There is a monotonic relationship with a negative slope between heart rate (HR) and AP amplitude. C fibers remain excitable for 25 days after cuff implant. (2) The anticonvulsant efficacy of VS is directly related to the fraction of vagal C fibers stimulated and the frequency of stimulation. (3) The anticonvulsant efficacy of VS has been established using two rat models of human epilepsy. VS abolishes the extensor component of the tonic phase of a MES and shortens or prevents tonic seizures induced by pentylenetetrazol (PTZ). (4) VS appears to act via release of large quantities of the inhibitory mediators GABA and glycine throughout large volumes of the brain. (5) It is rational to test VS in man as a treatment for intractable seizures.