Where is Acetylcholine made and released? And What are the receptors it binds to?
The Parasympathetic nerves. Binds to the muscarinic receptors.
What are the Muscarinic Receptors?
m1
m2
m3
m4
m5
What do the Muscarinic Receptors do generally?
m1,m2,m3-Increase Phospholipase C (Gq)
m2,m4-Inhibits Adenylate Cyclase (Gi)
Effects on Heart? And what receptor(s) and/ neurotransmitter cause them? (2)
m2 RECEPTOR + ACETYLCHOLINE
-Parasympathetic nerve to heart:
-Decreases force of contraction
-Reduces heart rate
What are the general Cardiac effects on the SAN and AVN (parasympathetic and sympathetic?
The Vagus nerve influences the SAN and atria
SAN-stimulated through parasympathetic innervation (cholinergic vagus nerves)
AVN-stimulated through sympathetic innervation (adrenergic vagus nerves)
Effects on Blood Vessels? And what receptor(s) and/ neurotransmitter cause them? (4)
m3 RECEPTOR + ACETYLCHOLINE
-Acetylcholine produces considerable vasodilation of systemic arteries
-But there is for less parasympathetic innervation to arteries
-Promotes the release of a gas (NO) from the endothelium
-Acetylcholine relaxes arteries due to m3 receptor activation in the endothelium
Effects on Male Genitalia? And what neurotransmitter cause them? (3)
m3 RECEPTOR + ACETYLCHOLINE
-One arterial bed with rich parasympathetic innervations=penis
-Stimulation of parasympathetic nerve=dilation of the penile artery
-Leads to the engorgement of the corpus
Effects on Non-Vascular Smooth Muscle? And what receptor(s) and/ neurotransmitter cause them? (3)
m3 RECEPTOR + ACETYLCHOLINE
Parasympathetic nerve activation causes contraction:
-bladder detrusor
-airway
-GI tract
What are the Effects of acetylcholine on non-vascular and vascular muscle cells?
(black cloud=endothelial cell which causes NO release when stimulated)
Effects on the Eyes? And what receptor(s) and/ neurotransmitter cause them? (3)
m3 RECEPTOR + ACETYLCHOLINE
-Contacts circular muscle=narrow pupil
Eye accommodation:
-Contraction of ciliary muscle
-Relaxes suspensory ligaments
-Allows lens to bulge
Effects on the Various secretions? And what receptor(s) and/ neurotransmitter cause them? (4)
m1 AND m3 + ACETYLCHOLINE
-Saliva
-Tears
-Gut Acid
-Sweat (sympathetic effect)
A general summary of the Muscarinic cholinoceptor-mediated responses
m1-Gut acid production and other secretions
m2-Decresed cardiac activity
m3-Contraction of visceral smooth
muscles, saliva production, release of NO from endothelium, pupil narrowing
m4-CNS
m5-CNS