Podcast
Questions and Answers
How is acetylcholine (ACh) released from vesicles at the synaptic cleft?
How is acetylcholine (ACh) released from vesicles at the synaptic cleft?
- By passive diffusion
- By exocytosis triggered by Ca2+ entry (correct)
- By active transport out of the neuron
- By endocytosis triggered by Ca2+ entry
What is the mechanism of action of atropine on cholinergic neurons?
What is the mechanism of action of atropine on cholinergic neurons?
- Blocking ACh release
- Blocking VAChT
- Blocking ChAT
- Blocking cholinergic receptors (correct)
Which drug blocks the enzyme responsible for the breakdown of acetylcholine (ACh)?
Which drug blocks the enzyme responsible for the breakdown of acetylcholine (ACh)?
- Vesamicol
- Neostigmine (correct)
- Botulinum toxin
- Hemicholinium
What is the function of vesamicol in relation to cholinergic neurons?
What is the function of vesamicol in relation to cholinergic neurons?
How does acetylcholine (ACh) travel across the synaptic cleft to bind with cholinergic receptors?
How does acetylcholine (ACh) travel across the synaptic cleft to bind with cholinergic receptors?
Which of the following is NOT a step in the cholinergic transmission of acetylcholine (ACh)?
Which of the following is NOT a step in the cholinergic transmission of acetylcholine (ACh)?
Which of the following organs receive innervation from both the sympathetic and parasympathetic divisions of the autonomic nervous system?
Which of the following organs receive innervation from both the sympathetic and parasympathetic divisions of the autonomic nervous system?
Which of the following is a characteristic of the parasympathetic nervous system (PNS)?
Which of the following is a characteristic of the parasympathetic nervous system (PNS)?
Which neurotransmitter is associated with the sympathetic nervous system (SNS)?
Which neurotransmitter is associated with the sympathetic nervous system (SNS)?
What is the function of naphthylvinylpyridine (NVP) in the context of cholinergic transmission?
What is the function of naphthylvinylpyridine (NVP) in the context of cholinergic transmission?
Which of the following organs receive only parasympathetic innervation?
Which of the following organs receive only parasympathetic innervation?
Study Notes
Storage of ACh
- ACh is actively transported into vesicles by VAChT, an antiporter.
- VAChT is blocked by vesamicol.
Release of ACh
- Release from vesicles occurs by exocytosis triggered by Ca2+ entry upon arrival of nerve impulse.
- ACh release is blocked by botulinum toxin (by inhibiting SNAP and VAMP).
Cholinergic Receptors
- Once released, ACh diffuses across the synaptic cleft to bind with cholinergic receptors on postsynaptic membrane (sometimes presynaptic).
- Cholinergic receptors are blocked by atropine (M) or tubocurarine (N).
Termination of ACh
- ACh is terminated by acetylcholinesterase (AChE).
- AChE is blocked by Neostigmine.
- Hemicholinium blocks HAChT.
Autonomic Pharmacology
- Study of how drugs interact with the ANS.
- Divisions of ANS: "Rest and Digest" (parasympathetic) and "Fight or Flight" (sympathetic).
Characteristics of ANS Divisions
- Parasympathetic: "Rest and Digest", cholinergic nerves, receptors: M, N.
- Sympathetic: "Fight or Flight", adrenergic nerves, receptors: α, β.
Thoracolumbar Outflow
- Organs that receive ONLY sympathetic innervation:
- Radial muscle of iris
- Muller's muscle
- Heart
- Arrector pili muscles
- Sweat Glands
- Bronchiole - Gland & smooth muscle
- Stomach
- Most Blood Vessels
- Spleen
- Adipose tissue
- Paravertebral Ganglia
- Adrenal medulla
- Kidney
- Intestines
- Bladder
- Prevertebral Ganglia
- Ejaculation muscle
Craniosacral Outflow
- Organs that receive ONLY parasympathetic innervation:
- Heart
- Bronchiole - Smooth muscle & gland
- Stomach
- Small Intestine
- Lacrimal Gland
- Sphincter (circular) muscle of iris
- Ciliary muscle
- Salivary Gland
- Large Intestine
- Bladder
- Genitalia
Cholinergic Transmission
- 5 steps in neurotransmission of ACh:
- Synthesis
- Storage
- Release
- Binding
- Termination
- ChAT is blocked by NVP.
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Description
Test your knowledge on the synthesis and metabolism of acetylcholine, along with topics such as autonomic pharmacology and neurotransmitter interactions. This quiz covers important concepts related to ANS drugs, cholinergic system, anticholinergic agents, sympathomimetic drugs, and adrenoceptor antagonists.
