Autonomic Cholinergic Physiology

Question 0

What is the major neurotransmitter in the ANS?

Answer 0

Acetylcholine

Question 1

What are the 2 major sites in which acetylcholine acts in autonomic transmission?

Answer 1

Communication between all Preganglionic and postganglionic autonomic neurons, communication between all postganglionic parasympathetic neurons and their target organs

Question 2

What is the postganglionic neurotransmitter that stimulates the target organ in the SNS?

Answer 2

Norepinephrine

Question 3

What type of stimulation slows the heart?

Answer 3

Vagal stimulation

Question 4

What is the transferable chemical mediator released by stimulation of the vagus nerve?

Answer 4

Acetylcholine

Question 5

Is ANS effects on target organs electrical or chemical?

Answer 5

Chemical

Question 6

What muscle in the eyes causes accommodation?

Answer 6

Ciliary muscle

Question 7

In general what are the effector functions of the PNS?

Answer 7

Smooth muscle contraction, glandular secretion, cardiac inhibition

Question 8

What are coupled to second messenger systems which in turn trigger the target cell response?

Answer 8

Muscarinic Ach receptors

Question 9

What type of receptors are metabotropic, trigger intracellular biochemical cascades, are relatively slow sustained processes, recruit multiple effectors, undergo amplification of signal?

Answer 9

Muscarinic ACh receptors

Question 10

How many ACh muscarinic receptor subtypes are there?

Answer 10

5

Question 11

What is the second messenger in muscarinic receptors (M3,M1,M5)?

Answer 11

IP3 (phospholipase C system)

Question 12

The binding of ACh to a muscarinic ACh receptor stimulates what type of G protein? (M3,M1,M5)

Answer 12

Gq

Question 13

What is the end product of the phospholipase C system, that triggers the opening of the ER lumen causing a large increase in intracellular Ca+?

Answer 13

IP3 (M3,M1,M5)

Question 14

The Gq protein stimulates what system to produce the second messenger IP3?

Answer 14

Phospholipase C system

Question 15

What type of ACh muscarinic receptors cause smooth muscle contraction and stimulation of secretion?

Answer 15

M3 (also M1,M5)

Question 16

The binding of ACh to a muscarinic ACh receptor stimulates what type of G protein? (M2,M4)

Answer 16

Gi

Question 17

Gi inhibits what from converting ATP to cAMP?

Answer 17

Adenylate Cyclase system

Question 18

What is the second messenger in muscarinic ACh receptors M2,M4 that is used to create PKA?

Answer 18

cAMP (adenylate cyclase system)

Question 19

A reduction in PKA has what effect on the heart?

Answer 19

Reduced contraction

Question 20

What stimulates cardiac muscle?

Answer 20

Increased adenylate cyclase

Question 21

What inhibits cardiac muscle?

Answer 21

Decreased adenylate cyclase

Question 22

What stimulates smooth muscle?

Answer 22

Increased phospholipase C

Question 23

What inhibits smooth muscle?

Answer 23

Increased adenylate cyclase

Question 24

What stimulates glands?

Answer 24

Increased phospholipase C

Question 25

What mediate the effects of vagal stimulation and lead to bradycardia?

Answer 25

M2 - muscarinic receptor

Question 26

In M2 muscarinic receptor vagal stimulation bradycardia can be induced in the SA node by what vagus nerve?

Answer 26

Right vagus

Question 27

In M2 muscarinic receptor vagal stimulation bradycardia can be induced in the AV conductive tissue by what vagus nerve?

Answer 27

Left vagus

Question 28

The binding of ACh to a M2 muscarinic ACh receptor causes what 2 effects?

Answer 28

Activation of K+ channels | Inhibition of adenylate cyclase

Question 29

Why aren't muscarinic receptors ideal for ganglionic transmission?

Answer 29

Too slow

Question 30

What type of receptor is used for all Preganglionic neuronal-ganglionic terminals?

Answer 30

Nicotinic acetylcholine receptors

Question 31

What properties of nicotinic ACh receptors make them ideal for Preganglionic neuronal cleft signaling?

Answer 31

Fast response - rapid onset, rapid offset | ACh held tightly within the cleft

Question 32

Receptor protein functions as an ion channel activation leads to Na+ influx ( and some Ca+ influx) leads to depolarization of post synaptic neuron and activation of postganglionic neuron describes what?

Answer 32

Ionotropic receptor (nicotinic receptor)

Question 33

What mediates transmission at both sympathetic and parasympathetic autonomic ganglia?

Answer 33

Acetylcholine acting at nicotinic ACh receptors

Question 34

Ionotropic receptors (ion channels), fast transmission ( order of milliseconds) and no 2nd messenger coupling is characteristic of what?

Answer 34

Nicotinic ACh receptors

Question 35

What are 2 nicotinic antagonists that block transmission?

Answer 35

Curare, hexamethonium

Question 36

Nicotinic receptor transmission is potentiated with what substance?

Answer 36

Acetylcholinesterases

Question 37

Different subtypes of nicotinic receptors exist do to different combinations of what in the pentameric ionotropic receptors?

Answer 37

Alpha, beta, gamma, delta, epsilon subunits

Question 38

What receptor subtype is found at the skeletal NMJ, causes depolarization and contraction, and has agonist of ACh and nicotine

Answer 38

Nm

Question 39

What receptor subtype is found in autonomic ganglia and the adrenal medulla cause depolarization and firing of post synaptic neurons and have agonists of ACh and nicotine?

Answer 39

Nn

Question 40

What subtype of nicotinic receptor is found in the brain and spinal cord, has pre-Junctional control of transmitter release, and has agonists of ACh and nicotine?

Answer 40

Ncns

Question 41

What are 2 examples of cholinesterases?

Answer 41

Acetylcholinesterases | Butyrylcholinesterase

Question 42

What has a high affinity for ACh, found at cholinergic synapses and neuroeffector junctions in pre and post synaptic membranes, important for termination of action of ACh released from neurons, choline re uptake important for recycling and synthesis of new transmitter describes what?

Answer 42

AChE

Question 43

Prefers butyrylcholine, also termed pseudocholinesterase or non-specific cholinesterase, present in plasma, function unclear, not important for termination of neuronally released ACh but important for termination of action of some cholinergic drugs describes what?

Answer 43

BChE

Question 44

AChE degrades ACh into what 2 constituents?

Answer 44

Choline and acetic acid

Question 45

What 2 constituents joined by choline acetyltransferase are needed to synthesize ACh?

Answer 45

Choline and acetyl-CoA