Pharmacology of the ANS Flashcards
Explain if the pre- and postganglionic neurone are myelinated for both the PNP and SNS (both branches of the ANS).
Both PNS and SNS are lightly myelinated preganglionically and unmyelinated postganglionically.
The somatic NS nerves do not synapse at a ganglion but travel as single nerves. Are they myelinated or not?
They are heavily myelinated.
What is the term given for where a neuron axon meets an effector tissue?
The neuroeffector junction.
How many types of PNS efferent configurations exist and what are they?
Include which type of receptor is at each point in the pathway.
X1 configuration =
1) Spinal cord > ganglia near effector tissue (ach = nicotinic receptor) > muscarinic receptor at neuroeffector junction (ach)
How many types of SNS efferent configurations exist and what are they?
Include which type of receptor is at each point in the pathway.
X3 configurations =
1) Spinal cord > ganglia near spinal cord (ach = nicotinic receptor) > adrenergic receptor at neuroeffector junction (NA = via alpha/beta adrenorrceptoes)
2) Spinal cord > ganglia near cord (ach = nicotinic receptors) > muscarinic receptor at neuroeffector junction (ACH!!! = via muscarinic receptors) (for sweat glands only!)
1) Spinal cord > adrenal medulla (ach = nicotinic receptors) > releases adrenaline and noradrenaline into the blood stream
What can be said about the ganglionic receptors of ALL ANS efferent pathways?
They all use NICOTINIC cholinergic receptors and acetylcholine.
What cells in the adrenal medulla synthesise and secrete adrenaline and noradrenaline?
The chromaffin cells
What are the X2 ANS receptor types?
1) cholinergic
2) adrenergic
What are the X2 subsets of cholinergic receptors?
1) muscarinic
2) nicotinic
What is the structure of muscarinic receptors?
How many subtypes are there and how are they named?
They are GPCR’s.
There is X5 subtypes named M1 —> M5 which are found at different locations within the body.
Where is the M2 muscarinic receptor most likely to be found?
What pathway does this receptor utilise?
In the heart.
It works via the Gi protein (opposing Gs) by decreasing levels of cAMP intracellularly.
Where is the M3 muscarinic receptor most likely to be found?
What pathway does this receptor utilise?
In the smooth muscle/glands.
It works via the Gq protein by increasing levels of ip3 and DAG which increases the intracellular calcium concentration.
What is the structure of nicotinic receptors?
How many subtypes are there and what are their names/structures?
They are channel receptors. Ach binds to open the channel for captions to flow through. This is why they are located at the ganglia of all ANS pathways.
There are X2 types:
1) N1 receptors = (alpha-1) X2 = (beta-1) = gamma = epsilon
2) N2 receptors
= (alpha-3) X3
= (beta-4) X2
What are the subtypes of the adrenergic receptors?
What are their subtypes?
Alpha and beta:
```
Alpha-1
Alpha-2
Beta-1
Beta-2
Beta-3
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In cholinergic transmission, what is acetylcholine synthesised from?
Which enzyme is responsible for this reaction?
Acetylcholine = synthesised from acetyl CoA and choline.
The enzyme that drives this reaction is acetyltransferase .
