Sweatman Ganglionic Blockers Flashcards
(21 cards)
Ganglionic blockers function by target…
antagonists of cholinergic Nicotinic (Nn) receptors
*this in entirely seperate from muscarinic antagonism
Ganglionic blockers work at which location
sympathetic ganglia
drugs active at sympathetic affect
> BV=tone of vascular
>Heart directly
only ganglionic blocker
trimethaphan
*mecylamine (inversine)–>orphan drug for tourrettes
is trimethaphan widely used
no ganglionic blockers have been replaced by Rx’s in the tx of HTN with more specificity and less global effects on ANS
Neurotransmitter in preganglion for sympathetic
acetylcholine
*therefore it is non-specific
Neurotransmitter for preganglion for parasympathetic
acteylcholine
*therefore it is nonspecific
Ligand gated ion channels in post synaptic membrane
Nicotinic Acetylcholine receptors
initial epsp is mediated through
Nicotinic ach receptor
slow IPSP and slow EPSP is mediated through
Muscarinic M2 and M1 receptors
Late slow EPSP is mediated through
several peptidergic receptors
arteriole predominant tone
sympathetic (adrenergic)
effect of ganglionic blockade on arterioles
vasodilation–>increased peripheral blood flow
veins predominant tone
sympathetic tone (adrendergic_
effect of ganglionic blockade on veins
dilaiton–>peripheral pooling of blood, decreased venous return, decreased CO
predominant tone in the heart
parasympathetic (cholinergeric)
effect of ganglionic blockade on heart
tachycardia
*loss of PS tone
result of ligand binding to Nicotinic receptor
opening of Na and K channels and DEPOLARIZATION
MOA FOR TRIMETHAPHAN and Mecylamine
compete with endogenous Ach for Nn receptor binding
*thereby tempering parasympathetic stimulation of postganglionic neurone
Adverse effect of ganglionic blockers
postural hypotension, tachycardia (loss of PS tone on the heart), arrhythmias
ancient ganglionic blocker that is no longer used
hexamathonium
