CNS Neurotransmission-Craviso

Question 1

What is the fcn of serotonin?

Answer 1

(5-HT) – sleep, arousal, mood, appetite

Question 2

What is the fcn of NE?

Answer 2

(NE) – mood; arousal, appetite

Question 3

What is the fcn of dopamine?

Answer 3

(DM) – movement (motor control); behavior; mood; perception

Question 4

What is the fcn of Ach?

Answer 4

(ACh) – arousal, cognition (memory and learning)

Question 5

What is the fcn of histamine?

Answer 5

wakefulness; equilibrium

Question 6

What are some excitatory AA in the CNS?

Answer 6

glutamic acid (glutamate)

Question 7

What are some inhibitory AA in the CNS?

Answer 7

gamma amino butyric acid (GABA)

glycine

Question 8

What are some important neuropeptides?

Answer 8

methionine & leucine enkephalin: pain transmission

substance P-pain transmission

Question 9

What are the functions of endocannabinoids? What is an example?

Answer 9

memory, cognition, pain perception
Ex: anandamide
2-AG: 2-arachidonylglycerol

Question 10

What is long hierarchical relay?

Answer 10

Transmission is highly sequential and interconnected neurons are related to each other in a hierarchical fashion - e.g., primary sensory and motor pathways
Ex: Pain transmission!
drugs that target pain transmission at the level of the cortex, thalamus, or spinal cord.

Question 11

What is non-hierarchical projecting?

Answer 11

Neurons from a single anatomical location extend multiple, divergent connections to target cells outside the region in which the neurons originate

Serotonin (5-HT) neurons project from the raphe nucleus
**includes ascending raphe & descending raphe projections

Question 12

What are functional aspects of non hierarchical projecting? Related to Serotonin

Answer 12

Sleep, arousal and mood
Behavioral changes
Hallucinations 
Feeding behavior 
Vomiting (via 5-HT3 ionotropic receptors in area postrema)

Question 13

Where do NE neurons project? This is related to non-hierarchical projecting.

Answer 13

Norepinephrine (NE) neurons project from the locus coeruleus
includes locus coeruleus projections & lateral tegmental projections

Question 14

What are the functional aspects of NE in nonhierarchical projecting?

Answer 14

Arousal and mood
Appetite
Cardiovascular control

Question 15

Related to nonhierarchical projecting & dopamine…what are the functional aspects?

Answer 15

Mood
Behavioral changes
Motor control
Neuroendocrine function (prolactin secretion)
Vomiting (area postrema)

Question 16

Where do the dopamine neurons project?

Answer 16

Dopamine (DM) neurons project from the midbrain, striatum and hypothalamus
mesocortical/mesolimbic pathways
nigrostriatal pathway
tuberoinfundibular pathway

Question 17

Where do ACh neurons project?

Answer 17

Cholinergic (Ach) neurons project from the forebrain and brainstem
basal forebrain pathways
mesopontine pathways

Question 18

What are the functional aspects of Ach neurons in non hierarchical projecting?

Answer 18

Arousal
Learning and memory
Motor control (in concert with dopamine)
Effects via muscarinic (G-protein linked) receptors and via nicotinic (ionotropic) receptors located presynaptically

Question 19

Where do histamine neurons project & what are its functional aspects in non hierarchical projecting?

Answer 19

Histamine neurons project from the hypothalamus
Functional aspects:
Arousal and wakefulness
Equilibrium (cerebellum)

Question 20

What are presynaptic ways to modulate NT?

Answer 20

Pre-synaptic: effects on synthesis, storage, release, reuptake and/or degradation of neurotransmitters (example-monoamine oxidase inhibitors); agonist or antagonist activity at nerve terminal autoreceptors

Question 21

What are postsynaptic ways to modulate NT?

Answer 21

Post-synaptic: receptor agonist, antagonist or modulatory activity; degradation of neurotransmitters (like acetylcholinesterase)

Question 22

NT receptors include metabotropic receptors. Describe them.

Answer 22

G protein coupled receptors
most common outside of CNS
This includes:

All known alpha and beta adrenergic, dopamine, muscarinic ACh, histamine, neuropeptide and endocannabinoid receptors
most 5-HT receptors
metabotropic glutamate and
GABA receptors

Question 23

NT receptors include ionotropic receptors. Describe them.

Answer 23

ligand-gated ion channels

outside CNS-at neuromuscular junctions

Question 24

GIve examples of ionotropic receptors that depolarize cells. Conduct Na+ or Ca++

Answer 24

AMPA (Na+), kainate (Na+) and NMDA (Ca2+ and Na+) classes of glutamate receptors
nicotinic ACh receptors (Na+ and Ca2+)
5-HT3 receptors (Na+)

Question 25

Give examples of ionotropic receptors that hyper polarize cells. Conduct K+ & Cl-

Answer 25

GABAA (Cl-) and glycine (Cl-) receptors

Question 26

Which induces a faster response...G protein coupled or ionotropic?

Answer 26

ionotropic must faster.

Question 27

What is excitatory transmission balanced by?

Answer 27

feed forward recurrent inhibitor actions by interneurons balance b/w EPSP & IPSP

Question 28

If you don't have a good balance b/w EPSP & IPSP?

Answer 28

comatose or seizures

Question 29

Which neurotransmission type predominates?

Answer 29

inhibitor neurotransmission

Question 30

HOw is GABA synthesized?

Answer 30

from glutamate enzyme: glutamic acid decarboxylase requires: pyridoxal phosphate

Question 31

How is GABA metabolized?

Answer 31

GABA-amino transferase in mitochondria of neurons & glial cells

Question 32

What is the difference b/w GABAa & GABAb?

Answer 32

GABAa: ionotropic chloride channel on the postsynaptic cleft GABAb: metabotropic G protein coupled; on pre & postsynaptic clefts

Question 33

The GABAb channel on the presynaptic cleft is coupled to what?

Answer 33

decreases calcium influx | decreases release of GABA or glutamate

Question 34

The GABAb channel on the postsynaptic cleft is coupled to what?

Answer 34

some to activation of K+ channels others coupled to Ca++ conductance IP3 production & inhibition of cAMP production

Question 35

When GABAb receptors on presynaptic clefts are bound...what is the result? Where are these receptors found in high concentration?

Answer 35

decreased release of GABA (less inhibition) decreased release of glutamate (smaller excitatory effect) high concentration in spinal cord

Question 36

WHat is a drug that acts as an agonist at GABAb receptors? What is it used to treat?

Answer 36

Baclofen aka Lioresal | used to treat spasticity (involuntary & abnormal muscle contractions) in individuals with ALS or MS

Question 37

What is the result of GABAa receptors?

Answer 37

they are chloride conducting ion channels hyperpolarizes postsynaptic cells & generates IPSPs can be phasic or tonic inhibition

Question 38

Where do you see tonic inhibition via GABA a receptors?

Answer 38

GABA released presynaptically goes to other sites. Extrasynaptic receptors are high affinity and are continuously activated by ambient GABA. Get continuous tonic inhibition.

Question 39

Where do you see phasic inhibition via GABAa receptors?

Answer 39

these happen in synaptic clefts | rapid synchronous opening of channels in cleft

Question 40

Glycine offers inhibitory neurotransmission. What are its actions in the spinal cord? What are its receptors?

Answer 40

control motor rhythm generation, coordination of reflex responses & processing of sensory signals, brain stem & reticular formation receptors Cl- conduction ion channels, NOT metabotropic.

Question 41

Which therapeutic agents that target glycine receptors?

Answer 41

none | but strychnine in rat poison antagonizes these receptors & is a powerful convulsant!

Question 42

Describe glutamate neurotransmission.

Answer 42

excitatory | glutamate reuptake on nerve terminals & on astrocytes, glial cells.

Question 43

What are the metabotropic receptors for glutamate?

Answer 43

they are located pre & post synaptically on astrocytes Group I mGluR receptors Group II & III mGluR receptors

Question 44

When Group I mGluR metabotropic glutamate receptors are bound...what is the result? HOw about when Group II & III are bound?

Answer 44

Group I: augment responses | Group II & III: decrease responses

Question 45

What are the 2 major types of ionotropic receptors for glutamate?

Answer 45

``` NMDA receptors (N-methyl D aspartate) Non-NMDA receptors ```

Question 46

What are the 2 types of Non-NMDA ionotropic glutamate receptors?

Answer 46

AMPA | Kainate receptors

Question 47

Which ion do AMPA receptors conduct? What is their function?

Answer 47

mainly Na+ & some Ca++ | mediate majority of excitatory synapses & play a role in neural plasticity

Question 48

Which ion do Kainate receptors conduct? What is their function? Where are they located?

Answer 48

Na+ & also Ca++ pre & post synaptically a role in neural plasticity

Question 49

What's the deal with NMDA glutamate receptors?

Answer 49

ionophores conduct mainly Ca++, but also Na+ co agonist is glycine & cofactor is Magnesium **externally binds glycine & glutamate & internally binds Mg+

Question 50

What is the function of NMDA glutamate receptors?

Answer 50

mediators of neural plasticity | long term changes in synapse structure & function--learning & memory

Question 51

Which gates open with normal synaptic release of glutamate? HOw about with strong depolarizing stimulus?

Answer 51

normal: AMPA or kainate | Strong depolarization: NMDA receptor is activated, Mg++ given the boot.

Question 52

What is long term potentiation?

Answer 52

increased sensitivity of post synaptic neurons to glutamate | more AMPA receptors brought to the surface in growing of dendrites w/ neural plasticity

Question 53

What is long term depression?

Answer 53

decreases sensitivity of post-synaptic neurons to glutamate fewer AMPA receptors at the surface neural plasticity pruning.