Autonomic Nervous System (2) Flashcards
(42 cards)
Location of ACh receptors in the ANS
Parasympathetic System
Adrenal Medulla of Sympathetic System
Location of Nicotinic ACh receptors
NMJ
Sympathetic Ganglia
Parasympathetic ganglia
Central Nervous system
Location of Muscarinic ACh receptors
Parasympathetic target organs
Sweat glands (sympathetic)
Vascular smooth muscle
CNS
Nicotinic ACh receptor
Ionotropic
Muscle - (alpha1)2 Beta1 Delta(3backwards)
Ganglia - (alpha3)2(beta2)3
Muscarinic ACh receptor
G-protein linked receptor (metabotropic)
Gq - M1 and M3 –> Increase IP3 and DAG
Gi - M2 –> decrease cAMP
Can we differentiate muscle from ganglion Nicotinic ACh receptors ?
Differences in subunits may allows for some specificity
Predominate Tone
Tissues innervated by both branches of the ANS
Effects of anti-cholinesterase on the ANS
(SLUDGE)
Salivation
Lacrimation
Urination
Defecation
Gastrointestinal upset
Emesis
Effects of anti-cholinesterase on ANS
Parasympathetic
Bradycardia
Hypotension
Broncho-constriction
Pupillary constriction (MIOSIS)
How can nicotinic and muscarinic receptors be differentiated ?
Nicotine binds to Nicotinic receptors
Muscarine binds to Muscarinic receptors
What affects both nicotinic and muscarinic receptors ?
Anything that influences storage and release of ACh will affect both receptor types.
How can muscarinic receptors be classified ?
Classified by their tissue distribution and their cellular response.
Not all muscarinic receptors are in the ANS
What muscarinic receptors are found in the CNS ?
M1,2,4,5
Where is M3 found ?
On vascular endothelial and smooth muscle cells
State the 3 muscarinic receptors that are under parasympathetic control
M1(neural)
M2 (cardiac)
M3 (glandular / smooth muscle)
M1
GLANDS : gastric, salivary, lacrimal
Autonomic ganglia
Gastric secretion
M2
HEART: Atria
Cardiac inhibition
M3
Gastric, salivary secretion
GI smooth muscle contraction
Ocular accommodation
Vasodilation
What is atropine ?
Muscarinic Antagonist
Muscarine receptor mediated effects
SLUDGE + Sweating
Nicotinic receptors effects
Changing between sympathetic and parasympathetic effects
Muscle weakness
Atropine effects
CNS mediated effects
Inhibition of muscarinic receptors
Describe :
-pilocarpine
-bethanechol
Non-selective muscarinic agonists
Show little or no selectivity between the subtypes of muscarinic receptor
Clinical uses of Pilocarpine
Constriction of pupils (Miosis)
Glaucoma (decrease IOP)
Xerostomia (following head/neck radiotherapy)
