Autonomic nervous system 2 Flashcards
What neurotransmitter receptor is involved in the innervation of skeletal muscle?
ACh (nicotinic)
What neurotransmitter receptor is involved in the innervation of blood vessels?
- Presynaptic to postsynaptic neurone synapse is ACh nicotinic
- On the synapse onto the target organ, noradrenaline
What neurotransmitter receptor is involved in the innervation of Sweat glands?
- Presynaptic neurone to postsynaptic neurone synapse is ACh (nicotinic)
- On the synapse onto the target organ, ACh muscarinic
What neurotransmitter receptor is involved in the innervation of the Adrenal medulla?
ACh nicotinic
What neurotransmitter receptor is involved in the innervation of the salivary glands?
ACh - nicotinic from presynaptic to postsynaptic ganglion
ACh - muscarinic receptor
Which division of the nervous system has acetylcholine receptors in all synapses?
Parasympathetic
What are the differences between the nicotinic acetylcholine receptors?
- Muscle: Two α1 units, β1, γ, δ
* Ganglia: Two α3 units, Three β2 units
What type of channel is the muscarinic receptor?
Metabotropic
What effect is there on a tissue if they are innervated by both the sympathetic and parasympathetic nervous system?
They are usually predominated by the parasympathetic nervous system
What does up regulation of signalling of acetylcholine at the target tissue cause?
SLUDGE effects: • Salivation • Lacrimation • Urination • Defecation • Gastrointestinal upset • Emesis Bradycardia, hypotension, Bronchoconstriction
Where are the nicotinic ACh receptors present?
- Neuromuscular junction
- Sympathetic ganglia
- Parasympathetic ganglia
- Central nervous system
Where are the muscarinic ACh receptors present?
- Parasympathetic target organs
- Sweat glands (sympathetic NS)
- Vascular smooth muscle
- Central nervous system
What are the agonists for the Muscarinic ACh receptor and what is the relative specificity of each?
- Acetylcholine (+++)
- Muscarine (+++)
- Bethanechol (+++)
- Pilocarpine (++)
What are the agonists for the Nicotinic ACh receptor and what is the relative specificity of each?
- Acetylcholine (+++)
* Nicotine (+++)
What is the main location of the M1 receptor?
- Autonomic ganglia
* Glands: Gastric, salivary, lacrimal etc.
What cellular response is caused by the M1 receptor?
- Increase of IP3
* Increase DAG
What is the functional response of the M1 receptor?
Gastric secretion
What is the main location of the M2 receptor?
In the atria of the heart (especially nodal tissue)
What is the cellular response of the M2 receptor?
Decreases cAMP (inhibits some of the heart’s processes)
What is the functional response of the M2 receptor?
Cardiac inhibition
Where is the main location of the M3 receptor?
- Exocrine glands: gastric, salivary glands etc.
- Smooth muscle: GI tract, eyes, airways, bladder
- Blood vessels: Endothelium
What are the cellular responses of the M3 receptor?
- Increased IP3
* Increase DAG
What are the function responses of the M3 receptor?
- Gastric and salivary secretion
- GI smooth muscle contraction
- Ocular accommodation
- Vasodilation
Which muscarinic receptors are found in the CNS?
M1, M2, M4, M5
Which muscarinic receptor is found on the vascular endothelial and smooth muscle cells?
M3
Give 2 agonists of the muscarinic ACh receptor
- Pilocarpine
* Bethanechol
Pilocarpine - Pharmacological properties and clinical uses
- non-selective muscarinic agonist
- Causes constriction of the pupil (miosis)
- Used to treat Glaucoma (to decrease intraocular pressure) (eye drops)
- To treat Xerostomia (dry mouth following head/neck radiotherapy) Orally/ spray
Bethanechol - Pharmacological properties and clinical uses
- Non-selective muscarinic agonist
- To treat bladder and gastrointestinal hypotonia
- poorly absorbed, readily excreted
What are the muscarinic ACh receptor antagonists?
- Atropine
- Glycopyrronium
- Hyoscine hydobromide
- Hyoscine butyl bromide
- Ipratropium
- Tropicamide
What are the pharmacological properties and clinical uses of Atropine
• Non-selective antagonist • Effects the CNs • Well absorbed orally - Bradycardia and cardiac arrest - Used as an adjunct for anaesthesia - Treat anti cholinesterase poisoning
What are the pharmacological properties and clinical uses of glycopyrronium
• Similar to atropine
• Doesn’t cross the blood brain barrier
- Similar clinical uses to atropine
What are the pharmacological properties and clinical uses ofHyoscine Hydrobromide
• Similar to atropine
• Affects the CNS
- Prevents hyper salivation
- Treats motion sickness
What are the pharmacological properties and clinical uses of Hyoscine butyl bromide
• Similar to Atropine but poorly absorbed
• Does not cross the blood brain barrier
- Treats GI spasms
What are the pharmacological properties and clinical uses of Ipratropium
• Delivered via inhaler ot nebuliser
• Doesn’t cross the blood brain barrier
- Maintenance treatment of COPD (chronic obstructive pulmonary disorder)
What are the pharmacological properties and clinical uses of Tropicamide
• Similar to atropine but shorter acting
- Ophthalmic use (mydriasis)
Describe the cause of glaucoma and describe its treatment
- Canal of Schlemm blocked so fluid cannot be properly drained, causes build up of pressure
- Trapicomide is used, it causes the constrictor muscle to relax, opening up the apature
