physiology

Question 1

synapsins

Answer 1

restraint
Ca++ entry activates kinases that phosphorylate synapsins and cause them to release the vesicles from actin filaments so they can move to the active zone

Question 2

Rab protein

Answer 2

targeting

hydrolysis of GTP -> GDP + Pi seems to allow the vesicle with Rab bound to target the docking site

Question 3

SNARE complex

Answer 3

VAMP (synaptobrevin) on vesicles bind to SNAP-25 and syntaxin-Munc 18 on the membrane allowing docking

Question 4

messing with SNARE complex

Answer 4

tetanus toxin cleaves VAMP
Botulinum A, B, C cleave SNAP-25, VAMP, and syntaxin, causing flaccid paralysis
alpha-lantrotoxin prevents SNARE release

Question 5

Synaptotagmin

Answer 5

binds Ca++ to allow vesicle fusion and exocytosis of neurotransmitters

Question 6

NSF

Answer 6

ATPase that uses SNAP to bind SNARE and unravel it

Question 7

presynaptic transporters

Answer 7

use Na+ gradient
glutamate transporter relies on Na+/K+ exchange
all other neurotransmitters rely on Cl-/Na+ cotransport

Question 8

vesicle transporters

Answer 8

use H+ gradient
VMAT 1 and VMAT 2 - monoamines (dopamine, NE, etc.)
VGAT - GABA
VAChT - ACh

Question 9

serotonin receptors

Answer 9

5HT3 - ionotropic
all others - metabotropic
triptans - agonists
ondansetron - block receptors

Question 10

time constant

Answer 10

Rm * Cm

Question 11

length constant

Answer 11

Rm/Ri

Question 12

Voltage gated K+ channels

Answer 12

present in CNS, rare in PNS

Question 13

HCN channels

Answer 13

hyperpolarization activated cation channels that open to allow faster depolarization

Question 14

types of K+ channels

Answer 14

delayed rectifier (slow)
Ca+ activated (creates a large after hyperpolarization phase)
A-type (rapid activation by depolarization)
M-type (slow activation by small depolarization, closed by ACh)

Question 15

voltage gated ion channel structure

Answer 15

4 subunits with 6 transmembrane domains each

have positively charged arginines and lysines

Question 16

CNS activation

Answer 16

no Na+ channel inactivation at rest -> easier to activate

HCN channels -> easier to refire