TBL 10 - Acetylcholine Agonists and Antagonists Flashcards
What type of nerve ending releases norepinephrine as the primary transmitter?
Adrenergic
What type of synapse uses norepinephrine as the primary transmitter?
Noradrenergic
What receptor binds to and is activated by one of the catecholamine transmitters or hormones (norepinephrine, epinephrine, or dopamine)?
Adrenergic receptor/Adrenoreceptor
What is the Baroreceptor Reflex?
The homeostatic mechanism that maintains a constant mean arterial BP with the sensory limb originating in the baroreceptors of the carotid sinus and aortic arch and the efferent pathways running in parasympathetic and sympathetic nerves to the heart and blood vessels.
What nerve ending releases acetylcholine?
Cholinergic
What receptor binds to and is activated by acetylcholine and related drugs?
Cholinoceptor/Cholinergic receptor
What nerve ending releases dopamine as the primary neurotransmitter and is also a synapse in which dopamine is the primary neurotransmitter?
Dopaminergic
What is the Homeostatic Reflex?
A compensatory mechanism for maintaining a body function at a predetermined level.
What is the Nonadrenergic/Noncholinergic (NANC) System?
A system that contains nerve fibers that are associated with autonomic nerves that release any transmitter other than norepinephrine or acetylcholine.
What constitutes the Parasympathetic Nervous System?
The part of the ANS that originates in CN III, VII, IX, and X (oculomotor, facial, glossopharyngeal, and vagus) and S2-4.
Craniosacral autonomic system.
What is a postsynaptic receptor?
A receptor located on the distal side of the synapse.
What is a presynaptic receptor?
A receptor located on the nerve ending from which the transmitter is released into the synapse.
What constitutes the Sympathetic Nervous System?
The part of the autonomic NS that originates in the thoracic and lumbar parts of the spinal cord.
The thoracolumbar autonomic system.
What does the Autonomic NS do?
Involuntarily regulates the activity of snooth muscles, exocrine glands, cardiac tissue, and endocrine and metabolic activities.
Where are the short preganglionic fibers of the sympathetic NS located?
Paravertebral chain
Where are the short preganglionic fibers of the parasympathetic NS located?
Innervated organs
What neurotransmitter acts on nicotinic and muscarinic receptors?
Acetylcholine
What NS are sweat glands part of and what neurotransmitter do they use?
Part of the sympathetic NS, are innervated by cholinergic fibers, and use ACh.
How is the adrenal medulla innervated?
Innervated directly by preganglionic sympathetic fibers.
How does Hemicholinum affect the synthesis of ACh?
Inhibits transport of choline into cholinergic nerve endings.
How does Vesamicol affect the storage of ACh?
Inhibits vesicle-associated transporter (VAT) which transports newly synthesized ACh into vesicles for storage.
How does calcium affect presynaptic neurons that hold ACh?
Calcium enters the neuron, depolarizing it, while also promoting the fusion of the vesicular membrane with the plasma membrane to allow for the exocytosis and release of ACh.
How does Botulism Toxin affect ACh release?
It blocks exocytosis, thereby inhibiting ACh release.
How do AChE inhibitors (ACEi) affect the termination of ACh?
They prevent the breakdown of ACh.
What kind of receptors are muscarinic receptors?
G-protein coupled receptors.
What type of receptors are M1?
Neuronal
What type of receptors are M2?
Cardiac
What type of receptors are M3?
Glandular
What pathway do M1, M3, and M5 receptors follow?
Gq:
- Activates PLC
- Increases IP3, DAG, and Ca
- PKC
What pathway do M2 and M4 receptors follow?
Gi:
- Inhibition of AC
- Decreased cAMP synthesis
- PKA
What type of receptors are nicotinic receptors?
Ligand-gated ion channels
Where are neuronal Nn type receptors located?
Ganglia, adrenal medulla, and brain.
Where are muscle Nm type receptors located?
Neuromuscular junction.
What are the muscarinic effects of M2 on the heart?
- SA node hyperpolarization leading to a decrease in impulse generation and bradycardia.
- AV node and PF (RP is increased causing slowing of conduction and partial/complete heart block.
- Decrease in force of contraction of atrial fibers.
- Decreased ventricular contractility.