CNS neurotransmitters

Question 1

what are the 2 major types of neurotransmitters?

Answer 1

small molecules ( classic neurotransmitters) and neuropeptides

Question 2

name the three main types and examples of other small molecule ( classical neurotransmitters)

Answer 2

acetylcholine (ACh), amino acids ( glutamate, GABA, glycine), biogenic amines ( dopamine, norepi, and epi)

Question 3

what is special about the amino acid neurotransmitters, glutamate, GABAand glycine?

Answer 3

they are in every synapse glutamate is excitatory, and GABA and glycine are inhibitory

Question 4

what are peptide neurotransmitters important for?

Answer 4

transmission and blocking of pain.

Question 5

what does removal of neurotransmitters from the synapse do?

Answer 5

terminate synaptic transmission

Question 6

the concentration of neurotransmitter w/in the synaptic cleft is tightly controlled via regulation of what 4 processes?

Answer 6

neurotransmitter synthesis, packaging, release and removal

Question 7

where are neuropeptide neurotransmitters made?

Answer 7

in the ER

Question 8

where are small molecule neurotransmitters made?

Answer 8

in the presynaptic terminal

Question 9

ligand gated ion channels are?

Answer 9

ionotropic

Question 10

G-prootein coupled channels are?

Answer 10

metabotropic

Question 11

Metabotropic neurotransmitters are ___________ than ionotropic transmitters

Answer 11

slower

Question 12

1 alpha and 1 beta are required to be what type of receptor?

Answer 12

GABA

Question 13

iontoropic receptors have how many subunits that contain how many transmembrane domains?

Answer 13

iontoropic receptors are usually 4-5 subunits that contain 3 or 4 transmembrane domains

Question 14

metabotropic receptors have how many transmembrane domains?

Answer 14

7

Question 15

what are the major biogenic amine neurotransmitters?

Answer 15

dopamine, norepinephrine, serotonin

Question 16

what is the major neurotransmitter in the neuromuscular junction of the peripheral nervous system and where else is it the major neurotransmitter?

Answer 16

acetylcholine which is also the major neurotransmitter in the parasympathetics

Question 17

where is acetylcholine synapse in the peripheral nervous system?

Answer 17

in the ganglia of the visceral motor sys

Question 18

what are the fmcs of Ach in the CNS?

Answer 18

attention, arousal, reward plasticity, enhances sensory fnc upon waking

Question 19

what is damage to the Ach sys ( cholinergic sys) in the CNS associated w/?

Answer 19

memory deficits in alzheimer’s

Question 20

what does acetylcholinesterase do?

Answer 20

it cleaves acetylcholine to acetate and choline ( this occurs in the synaptic cleft in the CNS and in the basal lamina in the periphery

Question 21

where is achetocholine degraded?

Answer 21

in the synaptic cleft

Question 22

sarin gas and other nerve gases and insecticides which inhibit acetylcholinesterase do what?

Answer 22

cause Sch to accumulate resulting in continued depolarization of the postsynaptic cell and leads to muscle paralysis at the neuromuscular junction.

Question 23

are acetylcholine receptors ionotropic or metabotropic?

Answer 23

there are both metabotropic (muscarinic)and ionotropic (nicotinic) Ach receptors

Question 24

where do ionotropic (nicotinic) acetylcholine receptors act?

Answer 24

in the periphery in the neuromuscular junction and also in the CNS

Question 25

where do metabotropic ( muscarininc) receptors act?

Answer 25

they mediate most Ach effects in the brain and they are involved in autonomic effector organs in the heart, smooth muscle etc.

Question 26

name 2 metabotropic Ach receptor antagonists.

Answer 26

atropine ( cause pupil dialation) scopolamine ( motion sickness)

Question 27

what is myasthenia gravis?

Answer 27

an autoimmune disease in which pts have antibodies against the muscle nicotic ( ionotropic) Ach Receptor leading to decreased receptors in the postsynaptic membrane, expanded synaptic cleft, and shallow junctional folds ( see pg 145)

Question 28

what are the symptoms of myasthenia gravis?

Answer 28

weakness, fatiguability in the arms and legs, difficulty speaking and swallowing, chewing , diplopia, and ptosis

Question 29

how do you treat myasthenia gravis?

Answer 29

by giving CHOLINESTERASE INHIBITORS to prevent the sparse number of Ach receptors the pt has from breaking down. or THYMECTOMY surgically remove the thymus or CORTICOSTEROIDS or IMMUNOSURPRESSANTS - to decrease the autoimmune response to AchRs

Question 30

What is the most prominent transmitter for normal brain fnc (CNS)?

Answer 30

glutamate

Question 31

and in crease in extracellular glutamate can lead to ?

Answer 31

excitotoxicity causing neurons to over excite and die

Question 32

excitotoxicity of glutamate is seen in which medical problems or disease?

Answer 32

strokes, hypoglycemia, trauma, and repeated intense seizures

Question 33

can glutamate cross the blood brain barrier?

Answer 33

no but glutamine can

Question 34

what happens to glutamate in glial cells?

Answer 34

they are converted to glutamine ( for transport out of cells) which prevents the excitotoxicity from occurring

Question 35

what are 3 types of glutamate receptors?

Answer 35

NMDA, AMPA and Kainate

Question 36

what are 3 unique properties of NMDA compared to the other glutamate receptors?

Answer 36

- ca2+ can pass through it - ion flow is voltage dependent because of the Mg2+ binding - glycine binding is required to the open channel

Question 37

where is GABA used in the CNS

Answer 37

in 1/3 of brain synapse , used in interneurons and purkinje fibers of the cerebellum

Question 38

where is glycine used in the CNS?

Answer 38

at synapses in the spinal cord.

Question 39

decreased GABA function can cause?

Answer 39

epilepsy

Question 40

excess glycine can cause ?

Answer 40

neonatal disease characterized by lethargy and mental retardation.

Question 41

glycine is made in nerve terminals from?

Answer 41

serine

Question 42

GABA is made in nerve terminals from?

Answer 42

glutamate

Question 43

where is glutamate made and used in the brain?

Answer 43

all over the place ( everywhere)

Question 44

what are GABA receptor agonists used for?

Answer 44

they are tranquilizers and control epilepsy and can be used to treat panic disorders and anxiety.

Question 45

what is an example of aGABA antagonists?

Answer 45

strychnine ( used in rat poison) it causes overactivity in spinal cord and brain stem leading to seizures

Question 46

where are biogenic amines synthesized in the brain compared to GABA?

Answer 46

the amines are synthesized in specific layers but their receptors are more broadly distributed.

Question 47

are biogenic amines released and removed from nerve terminals by the same means or different means?

Answer 47

by the same means ( they are les reliant on glial cells)

Question 48

are biogenic amines greatly used in the brain?

Answer 48

they are used by relatively few neurons in the brain but they are very important in maintenance of mental health

Question 49

a dopamine input to the corpus striatum is seen in what disease?

Answer 49

parkinson's disease

Question 50

cocaine interferes with the reuptake of what receptors?

Answer 50

dopamine receptors, therefore it raises dopamine levels

Question 51

what is the major fnc of dopamine?

Answer 51

involved in ovation, reward and reinforcement ( this takes place in the midbrain dopamine system)

Question 52

what is the minor dopamine fnc?

Answer 52

it is involved in emotional behavior ( localization of this involvement: in the projections to the cortex)

Question 53

dopamine receptors act by?

Answer 53

activating or inhibiting adenlyl cyclase

Question 54

why are ppl on amphetamines hyped up?

Answer 54

because it inhibits dopamine and norepi transporters causing an increase in release of them.

Question 55

although it is hard to clinically distinguish norepi and serotonin how are they different?

Answer 55

norepi is mood activating serotonin is mood altering

Question 56

what is the dopamine hypothesis?

Answer 56

that too much dopamine leads to psychosis

Question 57

what do anti-psychotic drugs block?

Answer 57

drugs block dopamine receptors

Question 58

what do anti- anxiety drugs (MAO inhibitors and _________)?

Answer 58

block the breakdown of biogenic amines and therefore increase biogenic amines and inhibitors of serotonin receptors

Question 59

what are the 3 classes of anti depressants include?

Answer 59

MAO inhibitors ( biogenic amine receptor breakdown) tricyclic anti-depressants ( block reuptake of Norepi) serotonin reuptake inhibiotrs ( like prozac)

Question 60

how are peptide neurotransmitters removed from the synaptic cleft ?

Answer 60

via degradation by peptidases

Question 61

see chart on 165

Answer 61

see chart