L17: Pharmacology Of The Autonomic NS Flashcards
What is the neurotransmitter released in parasympathetic pre-ganglionic neurones
Ach
What is the neurotransmitter released in parasympathetic post ganglion
Ach
What receptor does ach from the parasympathetic pre ganglionic neurone act on
Nicotinic receptor
What receptor does ach from the parasympathetic post ganglionic neurone act on
Muscarinic receptor
What neurotransmitter is released from the parasympathetic pre ganglionic neurone
Ach
What neurotransmitter is released from the sympathetic post ganglionic neurone
Noradrenaline or adrenaline
What receptor does ach from the sympathetic pre ganglionic neurone act on
Nicotinic receptor
What receptor does NA/A from the post ganglionic neurone act on
NA= alpha adrenoceptors Adrenaline= beta adrenoceptors
Which system can the adrenal medulla become involved in
Sympathetic NS
How can the adrenal medulla become part of the sympathetic ns
It can become innervated by sympathetic pre ganglionic neurones to release adrenaline/noradrenaline to effectors
What type of a receptor is nicotinic receptors
Ligand gated ion channels
How many sub units does a nicotinic receptor have
5
What type of a receptor is muscarinic receptors
G-protein coupled receptors
How many subtypes does muscarinic receptors have
5 therefore ranges from M1-M5
How many transmembrane segments does a muscarinic receptor have
7
What receptor does hexamethonium act on
Neuronal sub type of nicotinic receptor
What is hexamethonium
A selective non competitive antagonist
What does non competitive mean in terms of hexamethoniums action
Is does not bind to the same site as ach on the nicotinic receptor
What does hexamethonium result in
Blockage of all sympathetic and parasympathetic stimulation
Name a muscarinic aganoist
Muscarine
What is the action of muscarine
Mimics the actions of the parasympathetic
What is the action of muscarine on cardiac muscle
Decreased heart rate
What is the action of muscarine in smooth muscle
Vasodilation
What is the action of muscarine in exocrine glands
Increase secretions
What are the disadvantages of using muscarine
Muscarine poisoning
What are the effects of muscarine poisoning
Bradycardia Vasodilation and fall in BP Increased gut motility Bronchoconstriction Salivation
What is the treatment for muscarine poisoning
Atropine
What is atropine
A muscarinic competitive antagonist
What is pilocarpine
A muscarinic agonist
What receptor does pilocarpine act on
M3 on ciliary muscle
Where are M1 receptors located
Stomach
Salivary glands
Where are m2 receptors located
Cardiac muscle
Where are m3 receptors located
Smooth muscle
What is the clinical use of muscarinic antagonist
Asthma Bradycardia Decrease secretion Dilate pupils Motion sickness
What are the main 5 subtypes of adrenoceptors
Alpha 1 Alpha 2 Beta 1 Beta 2 Beta 3
Where are beta 2 adrenoceptors located
In the lungs
Where are beta 1 adrenoceptors located
In the heart
Where are beta 3 adrenoceptor located
Bladder
Name an agonist that acts on alpha 1 adrenoceptors
Pehylephrine
Name an agonist that acts on alpha 2 adrenoceptors
Brimonidine
What is happens inside the cell when noradrenaline binds to alpha 1 adrenoceptors
1) Binding of NA activates alpha 1 adrenoceptors which is a GCPRs
2) Gq protein dissociates and activates phospholipase c
3) phospholipase C produces IP3 and DAG
4) IP3 acts on IP3 receptors on endoplasmic reticulum to release calcium
5) calcium causes smooth muscle contraction
What is the G-protein of alpha 2 adrenoceptor sea
Gi
What is the G protein of all beta adrenoceptors
Gs
What is the G protein of M1 and M3 receptor
Gq
What is the G protein of M2 receptor
Gi
What does gi proteins lead to
Decrease in adenyl cyclase enzyme
Inhibition of CAMP messenger
What does gq protein lead to
Increase in adenyl cyclase enzyme
Stimulation in CAMP messenger
Which alpha adrenoceptor antagonist is used to treat hypertension
Doxazosin
Which alpha adrenoceptor antagonist is used to treat benign prostatic hyperplasia
Tamsulosin
Which beta adrenoceptor agonist is used to treat cardiogenic shock
Adrenaline
Which beta agonist is used to treat anaphylactic shock
Adrenaline
Which beta agonist is used to treat asthma
Salbutamol
How is noradrenaline recycled
Noradrenaline is taken back into the cell by noradrenaline transporter
Noradrenaline is Brocken down by monoamine oxidase
Which drugs can prevent the uptake of noradrenaline
Cocaine
Tricyclics antidepressants
What is the role of the enzyme monoamine oxidase
Break down noradrenaline, dopamine, serotonin
Which drugs can bind to monoamine oxidase irreversibly
Phenelzine
Traylcypromine
Maclobemide
