Neurotransmitters & Receptors

Question 1

What are the steps of the NT release?

Answer 1

1. Arrival of AP & terminal depolarization
2. Opening of voltage-gated Ca channels
3. Ca2+ enter synaptic terminal
4. Docking & fusion of vesicles to presynaptic membrane
5. Exocytosis: NT release into synaptic gap

Question 2

What are the ways to stop the action of a NT?

Answer 2

Reuptake, Degradation, Diffusion

Question 3

What is the criteria to be a NT?

Answer 3

1. Found in presynaptic terminal
2. Enzymes for synthesis
3. Release upon stimulation of the presynaptic neuron
4. Acts on a postsynaptic receptor and produces a biological effect
5. Can be inactivated
6. Predictable pharmacological action

Question 4

What are the major classes of NT?

Answer 4

Amino acids, amines, peptides, retrograde messengers

Question 5

What are the excitatory amino acids?

Answer 5

Glutamate and aspartate

Question 6

What does VGlut do?

Answer 6

Packages glutamate into vesicles

Question 7

What are the inhibitory amino acids?

Answer 7

GABA & Glycine

Question 8

What are the enzymes needed for GABA?

Answer 8

GAD transforms glutamate into GABA; VGAT fills vesicles

Question 9

What are the properties of glycine?

Answer 9

converted from serine; responsible for IPSPs in spinal cord; VIAAT

Question 10

What are the types of amines?

Answer 10

Acetylcholine, catecholamine, indoleamine

Question 11

What are the catecholamine NT?

Answer 11

dopamine, norepinephrine, epinephrine

Question 12

What does dopamine do? What is it made from?

Answer 12

Movement, learning, attention, emotion; Tyrosine –> DOPA –> Dopamine

Question 13

What is the Idoleamine NT?

Answer 13

Serotonin

Question 14

What does serotonin do?

Answer 14

Regulates mood, emotional behavior, sleep and arousal; Target system of hallucinogenic & antidepressant drugs

Question 15

What is Purine (ATP)?

Answer 15

Often packaged in synaptic vesicles with other NT an co-released during neurotransmission

Question 16

What are peptides?

Answer 16

Short chains of amino acids; synthesized in cell bodies, packaged in the Golgi, and transported to synaptic terminal via microtubles

Question 17

What are types of Retrograde messengers?

Answer 17

Endocannabinoids and soluable gases

Question 18

What is the role of endocannabinoids?

Answer 18

Widespread inhibitory function in CNS

Question 19

What is Dale’s principle?

Answer 19

The hypothesis that neuron releases the same NT at all its synapses

Question 20

What are the categories of NT receptors?

Answer 20

Ionotropic & Metabotrophic

Question 21

What are the properties of Ionotrophic receptors (transmitter-gated ion channels)?

Answer 21

• fast synaptic transmission
• sensitive detectors of chemicals
• directly regulate flow of ionic currents
• selective

Question 22

What are the steps of G protein-coupled receptors?

Answer 22

1. Binding of the NT to the receptor protein
2. Activation of G-proteins
3. Exchange of GDP to GTP
4. Activation of affecter systems

Question 23

What is the difference between ionotrophic and metabotrophic receptors? How many transmembrane domains does each have?

Answer 23

Metabotrophic are much slower, last for longer, and are extensively amplified.
Metabotrophic= 7 transmembrane
Ionotrophic = 4 transmembrane

Question 24

What are heteroreceptors?

Answer 24

Respond to NT other than the ones contained in its synaptic vesicle

Question 25

What are autoreceptors?

Answer 25

Respond to NT that are released from its own synaptic vesicle

Question 26

What are the essential components of signaling systems?

Answer 26

1. A molecular signal 2. A receptor molecule 3. A target effector molecule (response)

Question 27

What are the types of Molecular signals?

Answer 27

Cell impermeant; cell permeant; cell-associated

Question 28

What are cell-impermeant molecules?

Answer 28

Includes NT (do not readily cross membranes)

Question 29

What are cell-permeant molecules?

Answer 29

Includes steroid-based molecules, thyroid hormone and retinoids

Question 30

What are cell-associated molecules?

Answer 30

Cell membrane potentials to cell membrane receptor interactions of closely apposed cells

Question 31

What is exogenous?

Answer 31

Produced outside of the body

Question 32

What is an endogenous?

Answer 32

Produced within the body

Question 33

What is the cyclic nucleotide stimulatory pathway? What is an example of a NT?

Answer 33

I go to AC for Crap & Poker"; NT binds to receptor which changes the GPCR and GDP is exchanged to GTP. The Gs Alpha subunit stimulates adenyl cyclase. With the addition of ATP, cAMP releases PKA.; EX: norepinephrine

Question 34

What is the cyclic nucleotide inhibatory pathway? What is an example of a NT?

Answer 34

G4; NT binds to receptor and changes the GPCR. GDP is exchanged forGTP. Alpha subunit Gi stimulates guanyly cyclase. With the addition of ATP, cGMP stimulates PKG.; EX: Dopamine

Question 35

What is the lipid cascade pathway? What is an example of a NT?

Answer 35

G-CPID; NT binds to receptor and changes the GPCR. GDP is exchanged for GTP and the Alpha subunit Gq stimulates Phospholipase C. With PIP2, IP3 and DAG are formed. IP3 releases Ca2+, calmodlin, and camK2. DAG stimulates PKC; EX: Glutamate