Lecture 5

Question 1

SNAREs and vesicles

Answer 1

V-SNARE proteins attach to vesicles, T-SNARE proteins attach to release site, they join together to have the vesicle ready for release

Question 2

action potential and synapses steps

Answer 2

1- when AP arrives, depolarization causes voltage gated Ca2+ to open, Ca2+ flows in
2- Ca2+ activates synaptotagmin that pulls the ready vesicles to target site and makes them fuse with it
3- vesicles fuse with the membrane of the synapse, releasing their contents into the synaptic cleft
4- Ca2+ channels close, excess Ca2+ is removed
5- vesicle membrane is recycled
6- reuptake, transmitters collected by transporter molecules and reused

Question 3

SSRI

Answer 3

Selective seratonin reuptake inhibitors- cause seratonin to stay in synapse longer, causing longer effects (antidepressant)

Question 4

glutamate

Answer 4

the most common neurotransmitter in CNS, usually excitatory (causes depolarization)

Question 5

GABA

Answer 5

most common inhibitory transmitter in CNS

Question 6

norepinephrine and dopamine (DA)

Answer 6

catecholamines that are important to CNS modulators

Question 7

acetylcholine

Answer 7

nerve to muscles, and CNS modulator

Question 8

ionotropic receptor

Answer 8

direct ion gated

Question 9

metabotropic receptor

Answer 9

indirect action through second messengers

Question 10

Reception that results in depolarization

Answer 10

1- post synaptic ion channels are changed to allow positively charged ions to enter (like Na+)
2- inside of synapse becomes less negatively charged and neuron gets closer to threshold
3- neuron becomes more likely to generate an AP all on its own
4- neuron is said to be excited (EPSP)

Question 11

EPSP

Answer 11

Excitatory post synaptic potential

Question 12

reception that results in hyperpolarization

Answer 12

1- post synaptic ion channels are changed to allow negatively charged ions to enter (like Cl-)
2- inside of synapse becomes even more negatively charged and neuron gets farther from threshold
3- neuron becomes less likely to generate an AP all on its own
4- neuron is said to be inhibited (IPSP)

Question 13

IPSP

Answer 13

inhibitory post synaptic potential

Question 14

post synaptic potentials vs action potentials

Answer 14

PSPs: 
passive propagation (become smaller with distance)
graded (variable magnitude)
excitatory or inhibitory 
APs:
active propagation (do not decay with distance)
all or none
only one kind of action potential

Question 15

where on the axon has the highest concentration of voltage gated Na+/K+ channels?

Answer 15

the axon hillock, so easily initiate AP if EPSPs and IPSPs reaching it sum to threshold level

Question 16

why doesn’t poison dart frog poison itself

Answer 16

basis of effect is binding to a particular part of Na+ channels and permanently blocking them open, muscles seize up
its own Na+ channels have a single gene single amino acid difference
still works as a sodium channel but isn’t affected by toxin