Vagal Inhibition

F. Frank LeFever flefever at ix.netcom.com
Sun Apr 11 21:56:35 EST 1999


Richard has addressed the ambiguity just in considering the motor
(efferent) aspects of vagal activity; but it has sensory (afferent)
aspects as well, making the phrase even more ambiguous.  (n.b.: given
that its activities are not much like what we usually think of when we
say "motor" or "sensory", the alternative terms--with less "surplus
meaning" are preferrable)

I have not kept up with it, but I believe there is a considerable
literature on stimulation of the vagus and inhibition of seizure
activity; I do not understand it very well, and welcome comments from
someone who does--i.e., what is the exact mechanism of this action?

F. Frank LeFever, Ph.D.
New York Neuropsychology Group


In <v04011701b3369d4de3ee@[146.226.4.215]> rhall at uvi.edu (Richard Hall)
writes: 
>
>Peter,
>
>The vagus nerve sends projections to much of the body visceral organs.
 It
>originates in the brain stem and is very important in the control of
heart
>rate, gastric motility, digestive, and metabolic activities.  When the
>vagus sends messages to the heart, the heart rate slows.  When the
vagus
>sends messages to salivary glands, they secrete saliva.  Vagal
stimulation
>of the pupil causes the aperature to close (mydriasis.)
>
>One common term used in conjunction with vagal function is vagal tone.
>Increased vagal tone results in a slower heart rate, salivary
secretions,
>and pupillary constriction.  Decreased vagal tone has the opposite
effects.
>It is possible to inhibit the actions of the vagus which would
decrease
>vagal tone, but that is probably not what is implied by vagal
inhibition.
>
>You see vagal inhibition a potentially sloppy phrase.  Vagal
inhibition of
>the heart slows the heart rate.  Inhibition of the vagus accelerates
the
>heart rate.
>
>rlh
>
>
>At 7:47 PM +0100 4/11/99, Peter Moss wrote:
>>Hi, could anybody please give me a brief description of what this is?
>>Preferably in non-technical language,
>>
>>thanks,
>>
>>Pete
>
>Richard Hall, Associate Professor of
>Comparative Animal Physiology
>Division of Sciences and Mathematics
>University of the Virgin Islands
>St. Thomas, USVI  00802
>
>340-693-1386
>rhall at uvi.edu




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