Neurotransmitters and Receptors

Question 1

Define neurotransmitters

Answer 1

Chemical messengers that enable neurons to send signals to other neurons

Question 2

4 criteria for classifying neurotransmitters

Answer 2

1. Must be synthesized in presynaptic neurons
2. Must be stored in vesicles in presynaptic neurons
3. Must be released from presynaptic neuron axon terminal when an action potential is fired
4. Must affect the postsynaptic neuron the same way, whether it’s released from presynaptic neuron or applied experimentally

Question 3

3 examples of amino acid neurotransmitters

Answer 3

Glutamate, glycine, GABA

Question 4

5 examples of monoamine neurotransmitters

Answer 4

Serotonin
Histamine
Dopamine, norepinephrine, epinephrine (catecholamine)

Question 5

4 types of endogenous neuroactive substances that are not considered neurotransmitters

Answer 5

Neuromodulators (e.g. adenosine)
Neurotrophic factors
Neurohormones
Gasotransmitters

Question 6

Which of the classes mediates most of the fast inhibitory/excitatory functions in the brain?

Answer 6

Amino acids

Question 7

Which of the classes consists of the largest neurotransmitters?

Answer 7

Neuropeptides (endorphins, orexins, substance P)

Question 8

Which 2 of the small molecule neurotransmitter classes have rings in their structures?

Answer 8

Monoamines and catecholamine

Question 9

Major excitatory and inhibitory amino acid neurotransmitters

Answer 9

Glutamate: excitatory
GABA: inhibitory

Question 10

2 key roles of Astrocytes when it comes to GABA and glutamate

Answer 10

1. Supplying GABA and glutamate neurons with glutamine, which is a precursor for both neurotransmitters
2. Absorbing glutamate and GABA from the synapse; both roles are accomplished via the GABA-glutamine or glutamine-glutamine cycle

Question 11

Glutamate: key roles in the brain

Answer 11

Plays key roles in fast excitatory signaling, sleep/wake and learning

Question 12

GABA: key roles in the brain

Answer 12

Inhibitory signals, motor control, vision and anxiety

Question 13

Histamine: key roles in the brain

Answer 13

Sleep, circadian rhythms

Question 14

Histamine: key roles outside of the brain

Answer 14

WBCs, involved in immune responses, itching/allergies

Question 15

Dopamine: key roles in the brain

Answer 15

Movement, motivation, reward/addiction, hormones

Question 16

Dopamine: key roles outside of the brain

Answer 16

chemical messenger in kidney, GI tract, pancreas, blood vessels

Question 17

Serotonin: key roles in the brain

Answer 17

Mood, appetite, sexuality, sleep

Question 18

Serotonin: key roles outside of the brain

Answer 18

GI tract (intestinal motility), platelets, vasoconstrictor

Question 19

Norepinephrine: key roles in the brain

Answer 19

alertness, memory, attention

Question 20

Norepinephrine: key roles outside of the brain

Answer 20

Adrenal glands, fight or flight response

Question 21

Neurotransmitters only bind to and activate 2 types of receptors:

Answer 21

ionotropic receptors and G-protein couple receptors (GPCRs)

Question 22

Glutamate receptors

Answer 22

NMDA: Excitatory
AMPA, kainate: Excitatory
mGluR (1-8): Most are excitatory

Question 23

GABA receptors

Answer 23

GABAa: inhibitory
GABAb: inhibitory

Question 24

Serotonin receptors

Answer 24

5-HT 1,5: inhibitory
5-HT 3: excitatory
5-HT 2, 4, 6, 7: excitatory

Question 25

Histamine receptors

Answer 25

H1, H2: Excitatory H3: Inhibitory

Question 26

Dopamine receptors

Answer 26

D1, D5: excitatory D2, D3, D4: inhibitory

Question 27

Norepinephrine receptors

Answer 27

alpha1, beta1: excitatory alpha2, beta2, beta3: inhibitory

Question 28

Acetylcholine receptors

Answer 28

Muscarinic (M1): excitatory Mescarinic (M2): inhibitory Nicotinic (N): excitatory

Question 29

Opiod peptides receptors

Answer 29

all inhibitory

Question 30

Activated G-proteins can produce effects via either of 2 categories

Answer 30

1. G-protein gated ion channels 2. G-protein activated enzymes (activate a cascade of downstream signaling molecules)

Question 31

G-protein gated ion channels

Answer 31

effectors that produce a faster, transcient, more localized effect which can be excitatory or inhibitory, depending on the ion channel (triggers EPSP or IPSP)

Question 32

G-protein activated enzymes

Answer 32

effectors that produce a slower, more permanent and more widespread effect, and usually cause more complex changes that simple generation of an EPSP or IPSP

Question 33

Ionotropic receptors

Answer 33

Nicotinic, 5-HT3, AMPA, kainate, NMDA