Dopamine And ACh Flashcards
Which three main nuclei in the brain contains the acetylcholine cell bodies?
- Nucleus basalis
- Septal hippocamptal pathway
- Substantia nigra
How is acetylcholine made?
From choline in the diet and Aceyl-CoA from the Krebs cycle
Combined by acetyltransferase
How is acetylcholine stored?
Packaged into vesicles via vesicular ACh transporter which exchanges 2 x H+ for one molecule of ACh
How is acetylcholine released from it’s vesicle into the synaptic cleft?
Ca influx which is required for movement of the vesicle and docking to the pre-synaptic terminal
What are the three different types of ACh vesicles?
- Readily releasable
- Recycling phase
- Reserve
Which 5 ligand gated nicotinic ion channels does ACh act on?
Muscle nAChRs mature (alpha1)2 + beta1 + delta + e
Embryonic muscle (alpha1)2 + beta1 + delta + gamma
Neuronal nAChRs ganglion (alpha3)2 + (beta4)3
Neuronal nAChRs CNS (alpha4)2 + (beta2)3
Neuronal nAChRs CNS (alpha7)5
Which G-protein coupled muscarinic receptors do ACh work on?
M1 - Gq and GII M2 - Go and Gi M3 - Gq and GII M4 - Go and Gi M5 - Gq and GII
What are the two nicotinic ACh receptors?
Four transmembrane domain and ACh binding site
Heteropentomer - 2 x alpha 4, 3 x beta2
Homopentomer - 5 x alpha 7
What is the structure of the muscarinic ACh receptor?
7 transmembrane domains
Binding site for ACh found deep in the transmembrane protein
Hydrophilic binding pocket
How does ACh degradation for reuptake occur?
Has to be broken down to Choline and Acetic acid by acetylcholinesterases
Which drugs work on the nicotinic ACh receptors?
Full agonists - suxamethonium, nicotine
Partial agonists - Varenacline
Reversible antagonists - pancronium, vercuronium
Irreversible antagonists - alpha-bungarotoxin
Which drugs work on the muscarinic ACh receptors?
Full agonists - ACh, muscarine, oxotremorine M
Partial agonists - McN-A-343
Reversible antagonists - atropine, ipratropium, benztropine, procyclidine (CNS active)
Which drugs works on the reuptake mechanism of ACh?
Hemicholinium
Which drug works on the degradation pathway of ACh?
Rivastigmine, neostigmine, galatamine
Which recreational drugs work on the Acetylcholine pathway?
Nicotine
Scopolamine
Henbane