kenyon neurotransmission 2 Flashcards

1
Q

four types of receptors

A

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

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2
Q

ionotropic receptors also known as

A

ligand gated ion channels or channel linked receptors

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3
Q

ionotropic receptor structure

A

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

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4
Q

how do we get functional diversity in ionotropic receptors?

A

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

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5
Q

metabotropic receptors aka

A

GPCR

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6
Q

metabotropic receptor fxn in terms of ion

A

-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).

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7
Q

define orphan receptor

A

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

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8
Q

muscarinic and dopamine and adrenergic,

glutamate and GABA,

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

A

metabotropic!!!!

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9
Q

metabotropic receptor functional diversity

A

DON’T MIX AND MATCH

but the respective G protein pathways are basically unlimited

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10
Q

ionic power of metabotropic receptor

A

EPSP or IPSP, not huge action potentials

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11
Q

ionic power of ionotropic receptors

A
  • minor change of membrane potential

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

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12
Q

ELR (enzyme linked receptor) mech

A

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

also does a bunch of other stuff

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13
Q

intracellular receptors are mainly for?

A

unconventional NTs

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14
Q

list the major small molecule NTs (4)

A

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

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15
Q

ACh locations

A
  • neuromuscular junctions
  • preganglionic autonomic ganglia
  • post-ganglionic parasympathetic
  • many CNS neurons
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16
Q

how does ACh get made?

A

@presynpatic terminal

acetyl coA + choline —–> acetylcholin

^^^key enzyme: choline acetyltransferase

17
Q

how does ACh get deactivated?

A

happens in the synaptic cleft

gets inactivated by ACETYLCHOLINESTERASE

18
Q

How does the choline get recovered?

A

Na+/choline antiporter on the presynaptic terminal

19
Q

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

A

IONOTROPIC!!!!

20
Q

How conserved are the Nm or Nn receptors?

A

Nm = VERY conserved

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

21
Q

muscle nAChR types of subunits

A

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
22
Q

things that bind to the a1 subunit on Nm

A

ACh, nicotine, curare, bungarotoxin

23
Q

Neuronal NAChR structure

A

still pentamers

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

What does this mean?
lots of room for diverse pharmacology

24
Q

targets for skeletal muscle nACh receptors

A

curare, d-tubocurarine, succinylcholine, and alpha bungarotoxin

25
targets for neuronal nACh receptors
hexamethonium
26
muscarinic AChR--ionotropic or metabotropic?
metabotropic, so they're connected to G proteins that will eventually influence opening or closing ion channels
27
types of metabotropic AChR
M1-M5 found in many neurons, SM, and cardiac muscle!!!! (definitely not part of normal neuromuscular transmission)
28
what's the main fast excitatory NT in the nervous system?
GLUTAMATE | half of brain synapses are glutamatergic
29
glutamate recycling
-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
30
what passes through all the ionotropic glutamate receptors?
Cations!!!! all of them mediate EPSPs!
31
input slide
input slid
32
input slide
input slide
33
input slide
in
34
what passes through the pore of NMDA receptor?
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
35
what does Mg2++ do to NMDA receptors?
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
36
how can we pop the Mg++ out?
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
37
that one slide on just the NMDA picture
wait for lecture
38
slides on NDMA GRAPH
wait
39
slide on NDMA GRAPH
WAIT