kenyon neurotransmission 2

Question 1

four types of receptors

Answer 1

channel linked receptors
enzyme linked
GPCR
intracellular receptors (for unconventional NTs)

Question 2

ionotropic receptors also known as

Answer 2

ligand gated ion channels or channel linked receptors

Question 3

ionotropic receptor structure

Answer 3

single transmembrane multimeric protein that binds to NT and is the channel

Question 4

how do we get functional diversity in ionotropic receptors?

Answer 4

by mixing and matching subunits we can produce hundreds of types.

for each receptor, we can combine 4-5 different subunits for that particular receptor

Question 5

metabotropic receptors aka

Answer 5

GPCR

Question 6

metabotropic receptor fxn in terms of ion

Answer 6

-Binding of NT activates trimeric G-proteins; these G proteins directly and indirectly influence the opening and closing of ion channels

(along with a thousand other activities).

Question 7

define orphan receptor

Answer 7

a 7-transmembrane protein that looks like a metabotropic receptor, but we dunno what is its ligand

Question 8

muscarinic and dopamine and adrenergic,

glutamate and GABA,

histamine and serotonin, and purine receptors are part of what class?

Answer 8

metabotropic!!!!

Question 9

metabotropic receptor functional diversity

Answer 9

DON’T MIX AND MATCH

but the respective G protein pathways are basically unlimited

Question 10

ionic power of metabotropic receptor

Answer 10

EPSP or IPSP, not huge action potentials

Question 11

ionic power of ionotropic receptors

Answer 11

• minor change of membrane potential

- but if Ca++ flows through, it can initiate an AP

Question 12

ELR (enzyme linked receptor) mech

Answer 12

NT activates a tyrosine kinase that (1) directly or (2) indirectly opens or closes ion channels.

also does a bunch of other stuff

Question 13

intracellular receptors are mainly for?

Answer 13

unconventional NTs

Question 14

list the major small molecule NTs (4)

Answer 14

ACh
AAs(glutamate, aspartate, GABA, and glycine)
Biogenic amines (catecholamines, sertonin, and histamine)
Purines (ATP, ADP, and adenosine)

Question 15

ACh locations

Answer 15

• neuromuscular junctions
• preganglionic autonomic ganglia
• post-ganglionic parasympathetic
• many CNS neurons

Question 16

how does ACh get made?

Answer 16

@presynpatic terminal

acetyl coA + choline —–> acetylcholin

^^^key enzyme: choline acetyltransferase

Question 17

how does ACh get deactivated?

Answer 17

happens in the synaptic cleft

gets inactivated by ACETYLCHOLINESTERASE

Question 18

How does the choline get recovered?

Answer 18

Na+/choline antiporter on the presynaptic terminal

Question 19

Nicotinic AChR (Nm and Nn) are what kind of receptors?

Answer 19

IONOTROPIC!!!!

Question 20

How conserved are the Nm or Nn receptors?

Answer 20

Nm = VERY conserved

Nn = TONS of kinds (combine 4-5 subunits!)

Question 21

muscle nAChR types of subunits

Answer 21

both Nm and Nn have the same three subunits
-alpha 1, alpha 1, beta 1

differ in the last two subunits

• fetal mammals and torpedo: gamma and delta
• adult mammals: delta and epsilon

Question 22

things that bind to the a1 subunit on Nm

Answer 22

ACh, nicotine, curare, bungarotoxin

Question 23

Neuronal NAChR structure

Answer 23

still pentamers

alpha subunits: 1-10
beta subtunits: 1-4
a7: are Ca++ channels

What does this mean?
lots of room for diverse pharmacology

Question 24

targets for skeletal muscle nACh receptors

Answer 24

curare, d-tubocurarine, succinylcholine, and alpha bungarotoxin

Question 25

targets for neuronal nACh receptors

Answer 25

hexamethonium

Question 26

muscarinic AChR–ionotropic or metabotropic?

Answer 26

metabotropic, so they’re connected to G proteins that will eventually influence opening or closing ion channels

Question 27

types of metabotropic AChR

Answer 27

M1-M5

found in many neurons, SM, and cardiac muscle!!!!

(definitely not part of normal neuromuscular transmission)

Question 28

what’s the main fast excitatory NT in the nervous system?

Answer 28

GLUTAMATE

half of brain synapses are glutamatergic

Question 29

glutamate recycling

Answer 29

-some of the glutamate is simple reuptaked directly into the presynaptic terminal. The rest has to go through EEAT

• the glutamate from the synaptic cleft diffuses into EEAT channels on glial cells
• in the glial cell, glutamine synthetase (KEY) converts glutamate to glutamine.
• this glutamine then leaves the glial cell through SN1 channel, and then enters through SAT2 channels on the presynaptic neuron

Question 30

what passes through all the ionotropic glutamate receptors?

Answer 30

Cations!!!! all of them mediate EPSPs!

Question 31

input slide

Answer 31

input slid

Question 32

input slide

Answer 32

input slide

Question 33

input slide

Answer 33

in

Question 34

what passes through the pore of NMDA receptor?

Answer 34

Na+, K+, and Ca++..

@negative potentials, these receptors allow Na+ to come in
@positive potentials, K+ mostly goes out
@zero mV, the permeability of Na+ entering the cell is the same as the permeability of K+ leaving the cell!!!! so zero net permeability

Question 35

what does Mg2++ do to NMDA receptors?

Answer 35

it blocks the channel if the membrane potential is negative (below zero or resting)

consequence: NMDA receptors alone can’t do ANYTHING at the resting potential

Question 36

how can we pop the Mg++ out?

Answer 36

depolarization pops the Mg++ out of the NMDA channels.
how? neighboring AMPAs can depolarize the neuron, relieving the Mg++ block…. this eventually allows Ca++ to rush through the NMDA receptors

^great case of synpatic plasticity

Question 37

that one slide on just the NMDA picture

Answer 37

wait for lecture

Question 38

slides on NDMA GRAPH

Answer 38

wait

Question 39

slide on NDMA GRAPH

Answer 39

WAIT