Ch 8 Neurotransmitter reception

Question 1

How do Ionotropic receptors determine if they are opened or closed?

Answer 1

region near the center of the membrane

is narrowest and determines if the channel is opened or closed

Question 2

How is the nAChR opened?

Answer 2

2 ACh molecules bind cooperatively to open the channel binding causes twisting of the TM2 helices to make the pore wider

Question 3

nAChR structure

Answer 3

pentamer channels made of alpha and beta subunits arranged in endless possibilities.

Question 4

nAChR allow which ions through?

Answer 4

all cations(Na+, K+, Ca2+), calcium 20 times more likely to get in than Sodium

Question 5

GABAa receptors structure?

Answer 5

heteropentameric with 5 different subunits

Question 6

Which GABAa receptor has 6 subunits?

Answer 6

retina

Question 7

What can increase the inhibition caused by GABA?

Answer 7

barbiturates, alcohol and benzodiazapines (ie. valium), steroids, bicuculline, and penicillin

Question 8

glutamate receptor structure

Answer 8

each chain has 4ish transmembranehelices (really only 3)

Question 9

2 big glutamate receptor families

Answer 9

NMDA, AMPA

Question 10

GluR2

Answer 10

GluR2 is very different– poorly conducting

momomeric channels causes loss of rectification when expressed with GluR1 or GluR3

Question 11

How are NMDA receptors opened?

Answer 11

depolarization and glutamate

Question 12

What are NMDA receptors involved in?

Answer 12

involved in development, learning and memory, and neuronal damage after injury

Question 13

How is a NMDA receptor blocked?

Answer 13

at resting potentials of -40mV or so, a Mg2+ ion blocks the channel pore

Question 14

What gives NMDARs special signaling properties?

Answer 14

high Ca2+ permeability

Question 15

overactivation of NMDARs…

Answer 15

lets in too much calcium, damaging or killing cells

Question 16

Metabotropic Receptors

Answer 16

G-protein coupled receptors that bind to neurotransmitters

Question 17

How are metabotropic receptors different from ionotropic receptors?

Answer 17

generally slower than ionotropic receptors

generally longer lasting signals than ionotropic receptors

Question 18

GABA b receptors

Answer 18

work presynaptically as autoreceptors to inhibit release but also work postsynaptically to engage a long, slow hyperpolarization

Question 19

nAChR

Answer 19

Nicotinic acetylcholine receptor