Review of Pharmacology - 9E (2015)

Autonomic Nervous System
• Therefore, symptoms range from irritability, restlessness, ataxia, hallucinations
and delirium to drowsiness and sedation. Treatment is mainly supportive;
benzodiazepines are indicated when excitation predominates, whereas atropine
is contra-indicated because it may exacerbate delirium.
• Delayed mushroom poisoning is due to Amanita phalloides and Galerina species.
Principal toxins are amatoxins and act by inhibiting mRNA synthesis. Renal and
hepatic dysfunction results. Treatment is largely supportive and penicillin, thioctic
acid and silbinin may be effective antidotes.
Adverse effects
These include dry mouth, blurred vision (due to mydriasis and cycloplegia), urinary retention,
constipation, hyperthermia, confusion, delirium and restlessness etc. Anticholinergic drugs are
contra-indicated in glaucoma and BHP.
SYMPATHETIC NERVOUS SYSTEM
In this part of ANS, nor-adrenaline is the neurotransmitter at most of the sites. Circulating
tyrosine is transported into the neuronal cytoplasm where it is hydroxylated to form l-dopa
(di hydroxy phenylalanine). This rate limiting step is catalysed by an enzyme, tyrosine hydroxylase
that is amenable to inhibition by metyrosine. Latter can be used to control the discharge of
catecholamines during surgical removal of the tumor in patients with pheochromocytoma.
L-dopa is converted to dopamine by the action of a non specific decarboxylase (that also
decarboxylates 5-hydroxy tryptophan to serotonin), which can be inhibited by carbidopa and
benserazide. Dopamine is transported to the storage vesicles (inhibited by reserpine), where
tahir99 - UnitedVRG
Rate limiting enzyme in
catecholamine biosynthesis is
tyrosine hydroxylase
Autonomic General Pharmacology
Nervous System
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