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Author8 Posts

why acetocholine has a negative inotropic effect on atria


muscarinic receptor stimulation at SA node --dec hrt rate-neg inotropy


Major parasympathetic neurotransmitter think-rest and digest.
But I agree with K.


inotropic means contractility
Ach ----dec. HR throug Muscrinic R. at SAN----- -ve chronotropic
however, Ach decrease contractility by decreasing intracellular calcium
throug decreasing ca influx during plateu phase....."only in Atria"----- -ve


presynaptic inhibition of sympathetic nerve terminals in the ventricles


Plz ssrpk tell me....
How does Ach make presynaptic inhibition of the Sympathetic N terminal to ventricle??????? :?:


M2 receptors coupled to Gi protein, however they are predominantly present in the atria but some wht also present in small amounts in the ventricles whihc probably only limits sympathetiuc activity!

however with PANS it;s -ve chronotropism tht is more important!


Mmmmmm,,,,Thanks ssrpk

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