Does anyone know what happens to the firing rate of glossopharyngeal afferents and vagal afferents during carotid massage. I thought that the vagal rate would increase as to stimulate a parasympathetic response to lower the blood pressure and heart rate. Thanks for you help.
~Meddancer
mdwannabe Forum Guru
Topics: 37 Posts: 1,133
11/18/04 - 01:10 PM
#2
as far as I know, there is an inhibition of the inhibitor going on there. Normaly it is firing at certain rate to ihibit the discharges at X. Once more stretch aplied, less impulses at inhibitor site, so X discharges go up, thus activating PNS responce to he heart. ___________________ "Life not lived for others, is not worth living" Uncle Einstein "A life is not important, except in the impact it has on other lives" -Jackie Robinson
mani Forum Guru
Topics: 104 Posts: 1,403
11/18/04 - 03:42 PM
#3
firing rate of ipsilateral herrings nerve will increase which will lead to dec BP n HR. As a result firing rate of contralet herring nerve and of vagi will dec ___________________ Sincerity and hard work are the keys to success!
adeelmd Forum Elite
Topics: 40 Posts: 401
11/18/04 - 08:34 PM
#4
it would be exactly the same as if the bp increased. I don't know anything about ipsilateral or contralateral, but what you said meddancer is in the kaplan book....
to mani.. herring nerve??? the only time i've heard of that is in the herring-bruer reflex??? not in this? ___________________ where i lay my head is home.
meddancer Forum Junior
Topics: 13 Posts: 37
11/19/04 - 10:18 AM
#5
Thanks guys, I guess I'm just confused becasue in the kaplan book it has the vagus firing decreasing with carotid massage. I thought it would increase its firing and that would then cause a drop in bp and heart rate. It seems like the increase firing of the glossopharyngeal nerve is what causes the barorecptor reflex.
katzung Forum Guru
Topics: 72 Posts: 528
11/22/04 - 10:15 AM
#6
each time you massage carotid bodies the inhibitory influence which the nerves have on sympathetic outflow will be enhanced, which means reinforcement of the inhibition of the inhibitory impulses.
to make things simple the sympathetic stimulus to heart is inhibited. which would decrease the heart rate as well as causing reduced firing rate of Sa node as well as increased block of conduction thru Av node.
This is the principle behind using carotid sinus massage in proxysmal supraventricular tachycardia HOPE I HAVE HELPED :idea: ___________________ Hari Om,Lokaha Samasthaha Sukhino Bhavanthu (Let All Beings Everywhere Be Happy And Content) Proud to be an Indian.
mani Forum Guru
Topics: 104 Posts: 1,403
11/24/04 - 10:02 PM
#7
"adeelmd" wrote: to mani.. herring nerve??? the only time i've heard of that is in the herring-bruer reflex??? not in this?
herrings nerve is carotod body afferent, branch of CN IX ___________________ Sincerity and hard work are the keys to success!
