Autonomic Pharmacology Flashcards
Why do all drugs that enter the blood stream have a direct effect on the autonomic nervous system?
Neurones of the ANS are outside of the BBB
What is the class of drugs called that promotes the action of noradrenaline or inhibits the action of ACh on mAChR's? Give an example
sympathomimetric
e.g. atropine (muscarinic/nicotinic anatagonist) binds to the mAChR and causes the dilation of pupils
What is the class of drugs called that promotes the action of ACh on mAChR's or inhibit the action of noradrenaline? Give an example
parasympathomimetric
muscarine, ACh and pilocarpine
propanolol (NA antagonist, slows HR and lowers BP)
What effect does the botulinum toxin have?
What symptoms and signs does it produce?
stops exocytosis of ACh
What does neostygmin do?
What is it used to treat?
increases ACh by inhibiting ACh breakdown by acetylcholineesterase
Treats myaesthenia gravis
What type of drug is hexamethonium?
Where does it act?
In the past what was it used for?
selective antagonist for the neuronal subtype of nicotinic receptor
Non-competive so ACh can still bind but will have no effect
Acts at autonomic ganglionic receptors blocking all effects of ANS
Antihypertensive
What often causes muscarine poisoning?
What are the adverse effects?
What is the cause of these effects?
What is the treatment?
ingesting certain mushrooms
bradycardia, vasodilation, hypotension
increased gut motility
salivation, lacrimation, airway secretion
Muscarine is a muscarinic against so stimulates parasympathetic action
Atropine which is an antagonist and blocks receptors
What type of drug is pilocarpine?
What does it treat?
How?
Muscarinic agonist
Treats glaucoma, ciliary muscle constrict improving aqueous humour drainage, decreases intra-ocuclar pressure
What are the 5 areas of adrenergic transmission pharmacology?
- alpha-adrenoreceptor agonists/antagonists
- beta-adrenoreceptor agonists/antagonists
- Noradrenaline transporter blockers
- Monoamine oxidase inhibitors
- Indirectly acting sympathomimetic amines
What are the 5 main sub-types of adrenoreceptors?
- alpha 1 –> vasoconstriction
- alpha 2 –> vasoconstriction, inhibits sympathetic outflow
- beta 1 –> increase heart rate and contractility
- beta 2 –> relax smooth muscle (vaso/bronchodilation)
- beta 3 –> relax smooth muscle (bladder), stimulate lipolysis
What class are adrenergic receptors in?
GPCR’s
What are the main uses of alpha-receptor agonists? Give drug examples
vasoconstrictors with LA’s (adrenaline)
nasal decongestants (phenylephrine)
hypertension
facial erythema in rosacea (brimonidine)
What are the 3 main uses of beta-receptor agonists?
cardiogenic shock - B1 (adrenaline)
anaphylatic shock - a/b (andrenaline)
asthma B2 (salbutamol)
What are the 2 main uses of alpha antagonists?
hypertension (a1)
bening prostatic hyperplasia (a1)
What are the 5 uses of beta antagonists? (beta blockers)
angina hypertension anxiety heart failure locally for glaucoma e.g. metoprolol, propanolol
Some drugs act by preventing reuptake of noradrenaline to be recycled. What affect does this have in terms of autonomic activity? Give one drug example
Enhances the effects of sympathetic activity
Cocaine/desipramine
What are mono-amine oxidase inhibitors clinically used as?
What is their effect?
antidepressants
increase levels of noradrenaline, dopamine and 5-HT in the brain and peripheral tissues
Give an example of an indirectly acting sympathetic amine?
What are they structurally related to?
Mimic effects of ………….. but are ……….. …………
amfetamine
noradrenaline
longer lasting
What is the effect of botulinum toxin?
BT = blocks exocytosis of vesicles
Why do drugs that affect neuronal NAChR’s not affect muscular NAChR’s?
Different structure
Muscular have an alpha1 subunit
Neuronal have an alpha2-7 subunit
What are the symptoms of muscarine poisoning?
What is the treatment?
abdo pain/cramping bradycardia decreased BP secretions into airways airways contract
muscarinic antagonist e.g. atropine
What is pilocarpine used for?
What does it treat?
constricts pupil
glaucoma, stops XS secretions in aqueous humour
Where are each of the muscarinc ACh receptors found?
M1 - stomach, salivary glands
M2 - cardiac
M3 - smooth muscle
Which adrenoreceptors/muscarinic ACh receptors are connected to which G proteins?
A1 - Gq -->PLC A2 - Gi --> decrease AC All beta - Gs --> increase AC M1 - Gq --> PLC M2 - Gi --> decrease AC M3 - Gq --> PLC
