CNS Transmission

Question 1

Sympathetic activation occurs by

Answer 1

noreadrenaline acting on alpha and beta adrenoceptors

Question 2

Parasympathetic activation occurs by

Answer 2

ACh activating muscarinic receptors on peripheral, post-ganglionic neurons targeting tissue

Question 3

GPCRs involve

Answer 3

second messenger systems, more visceral responses over seconds

Question 4

Somatic activation occurs by

Answer 4

ACh acting on nicotinic receptors (ligand-gated ion channel)

Question 5

What are the requirements for chemical neurotransmission?

Answer 5

synthesis and storage of NT; release of NT; inactivation of NT; and receptors (pre and post-junctional)

Question 6

What are the targets for drug action on chemical neurotransmission?

Answer 6

enzymes, carriers, receptors, ion channels

Question 7

What is the mechanism of inactivation of NA?

Answer 7

uptake

Question 8

What is the mechanism of activation of ACh?

Answer 8

metabolism

Question 9

Cocaine inhibits

Answer 9

neuronal re-uptake of noradrenaline

Question 10

Amphetamine and ephedrine have what action on neuronal uptake?

Answer 10

substrates for uptake carrier - taken into nerve, displace NA, promoting its release

Question 11

What are the neurotransmitter receptors within the CNS?

Answer 11

ligand-gated ion channels and GPCR

Question 12

What are the types of CNS ligand-gated ion channels?

Answer 12

excitatory (nicotinic) - depolarize to Na+ influx; inhibitory (GABA A) hyperpolarize to Cl- influx

Question 13

What type of receptors do NA and dopamine use?

Answer 13

GPCRs

Question 14

What is the function of activation of GPCRs in the CNS?

Answer 14

activation of second messengers to modulate ion channel or enzyme activity

Question 15

Post-synaptic NT receptors are located

Answer 15

in dendritic regions

Question 16

Pre-synaptic NT receptors are located

Answer 16

in axon terminals

Question 17

Post-synaptic NT receptors are involved in

Answer 17

AP generation and modulation

Question 18

Pre-synaptic NT receptors are involved in

Answer 18

NT release

Question 19

The noradrenergic system distributes to

Answer 19

cerebral cortex, cerebellum, descending pathways through brainstem to CV and respiratory centres - diffuse, widely acting

Question 20

The noreadrenergic system produces

Answer 20

stimulant effects, mood, appetite, cardiovascular

Question 21

The dopaminergic system distributes

Answer 21

more discretely than NA; cell bodies in substantia nigra, ventral tegmental area going up to striatum (motor control), frontal and prefrontal cortex (perception of environment), pituitary

Question 22

Dopamine is involved in pathways for

Answer 22

movement (PD), behaviour (SCZ), dependence (via nucleus accumbens and ventral tegmental area), pituitary (prolactin)

Question 23

Cocaine blocks uptake of

Answer 23

dopamine > noradrenaline and serotonin

Question 24

Dopaminergic actions of cocaine are linked to

Answer 24

dependence (inhibits reuptake)

Question 25

Noradrenergic/serotonergic actions of cocaine are the basis for

Answer 25

antidepressant drugs (inhibits reuptake)

Question 26

Cocaine blocks what type of channels?

Answer 26

Na+ (at slightly higher concentrations) - basis for local anaesthetics

Question 27

What is the general cause of Parkinson's?

Answer 27

degeneration of dopaminergic pathways

Question 28

What are the treatments for PD?

Answer 28

L-DOPA (precursor to dopamine) + peripheral dopa-decarboxylase inhibitor (inhibits peripheral conversion of dopamine); monoaminoxidase B inhibitors to decrease dopamine metabolism; dopamine receptor agonists; muscarinic receptor antagonists

Question 29

What is the general cause of Huntington's?

Answer 29

GABA deficiency

Question 30

What are the treatments for Huntington's?

Answer 30

Baclofen (GABA agonist); chlorpromazine (dopamine antagonist)

Question 31

Glutamate is

Answer 31

excitatory

Question 32

GABA is

Answer 32

inhibitory

Question 33

Dopamine is

Answer 33

excitatory and inhibotry (receptor-dependent)

Question 34

Serotonin is

Answer 34

excitatory and inhibitory (receptor-dependent)

Question 35

Synapses in the CNS can be

Answer 35

excitatory OR inhibitory (depending on NT) but not both

Question 36

How do astrocytes regulate signalling?

Answer 36

regulate GABA and glutamate levels; transfer AAs from blood to neurons

Question 37

How are supporting cells involved in neuronal survival?

Answer 37

astrocytes - regulating neuron signalling (joins neuron to circulation, regulates GABA/glutamate, AAs); microglia - immune surveillance; generally, pH regulation and ECF homeostasis to maintain optimal CSF for neuronal firing; secretion of neurotrophic factors for development and survival

Question 38

Neurotrophic factors act on

Answer 38

tyrosine kinase receptors