- Aug 7, 2022
- 1 min read
Drugs Modifying Adrenergic Transmission
α Methyl-p-tyrosine
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Inhibits tyrosine hydroxylase (The rate-limiting enzyme)
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Depletes catecholamines
α Methyldopa
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Inhibits dopa decarboxylase
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Instead of noradrenaline, α methyl adrenaline is produced
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A false transmitter
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Does not stimulate receptor
Guanethidine & Bretylium
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Inhibit nerve impulse coupled release of neurotransmitters
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Decreased adrenergic activity
Receptor agonists e.g. phenylephrine, salbutamol etc.
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Stimulate receptors
⣠Increased adrenergic activity
Receptor antagonists e.g. phentolamine, propranolol etc.
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Block receptors
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Decreased adrenergic activity
Cocaine & Desipramine
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Inhibit axonal uptake by NET
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Noradrenaline stays in synaptic cleft
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More stimulation of the receptors
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Increased adrenergic activity
Reserpine
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Inhibits vesicular uptake by VMAT
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More noradrenaline stays in cytoplasm
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Degraded by MAO
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Decreased adrenergic activity
Amphetamine, Tyramine etc
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Displaces noradrenaline from its storage sites
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Noradrenaline moves into cytoplasm
⣠Reverse transport & exchange diffusion
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More noradrenaline in the synaptic space
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Stimulation of receptors
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Increased adrenergic activity
MAO inhibitors e.g. tranylcypromine
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Inhibits MAO
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Catecholamines are not degraded
COMT inhibitors
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Inhibits COMT
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Catecholamines are not degraded
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