lecture 13 - ligand gated ion channels

Question 1

neurotransmitters

Answer 1

chemical messengers released from one neuron and acting at a close site on another to elicit an effect determined by the specific nature of the receptor

Question 2

agonists

Answer 2

ligands that cause a postsynaptic effect

Question 3

antagonists

Answer 3

ligands which block the action of the agonist

Question 4

acetylcholine

Answer 4

voluntary movement of the muscles

Question 5

glutamate

Answer 5

major excitatory neurotransmitter, roles in memory and learning

Question 6

dopamine

Answer 6

motivation, pleasure associated with addiction and love

Question 7

serotonin

Answer 7

emotions, wakefulness and temperature regulation

Question 8

GABA

Answer 8

major inhibitory neurotransmitter

Question 9

ATP

Answer 9

neuronal communication, role in pain regulation

Question 10

ionotropic

Answer 10

agonist binds onto a receptor and the receptor itself is an ion channel

Question 11

metabotropic

Answer 11

receptors where ligand binds to receptor and it triggers a cascade of reactions that may lead to opening or closing of ions channels

Question 12

reversal potential

Answer 12

same as equilibrium potential

Question 13

the contents of one vesicle of neurotransmitter is referred to as a

Answer 13

quanta

Question 14

single vesicles are released spontaneously and their postsynaptic response is called a

Answer 14

mini

Question 15

nicotinic ach receptors

Answer 15

found at the neuromuscular junction
permeable to sodium, potassium and calcium
composed of 5 subunits, 2alpha, 1beta, delta and epsilon
alpha subunit binds ACh (therefore 2 ACh bind per receptor)
sigmoidal curve means there must be more than one binding site

Question 16

myasthenia gravis

Answer 16

autoimmune disease
body produces antibodies against ACh receptors
EPP cant generate muscle stimulation

Question 17

GABA and glycine

Answer 17

GABAa GABAc and glycine are ionotropic receptors (GABAb is metabotropic)
all pentameric structures
amino acids that line the pore dictates whether they let through anions or cations
the subunits create a lock and key form that influences what can bind

Question 18

5HT

Answer 18

is also a pentameric structure

Question 19

each subunit has 4 transmembrane domains

Answer 19

the the amino acids on the 2nd domain dictates the permeability as its the central one

Question 20

glycine and gaba are permeable to chloride and bicarbonate

Answer 20

tend to refer to these as inhibitory
the membrane potential is the average of all the ion channel that are open
when you open new channels the affect is always to push the cell to the reversal potential of the new channels that has opened
if the reversal potential is below membrane potential it prevents action potential from happening

Question 21

subunit composition dictates

Answer 21

1. receptor properties (sensitivity, conductance etc)
2. cell surface distribution
3. dynamic regulation

Question 22

purinergic receptors

Answer 22

permeable to cations, therefore excitatory
their ligand is ATP