Synaptic Structure/Function

Question 1

Chemical Synapse

Answer 1

Release Neurotransmitters
Act upon postsynaptic receptors
Unidirectional

Question 2

Electrical Synapse

Answer 2

Coupling through Gap junctions.
Connexins assemble into connexons
Bidirectional

Question 3

Synaptic Buton

Answer 3

A specialized area within the axon of the presynaptic cell that contains neurotransmitters enclosed in small membrane-bound spheres called synaptic vesicles

Question 4

Postsynaptic Density (PSD)

Answer 4

A protein dense specialization attached to the postsynaptic membrane. Postsynaptic molecular Machinery

Question 5

Clear vesicles

Answer 5

• Most frequently: ~50 nm
• Round or flattened
• Contain fast neurotransmitters: Glutamate and/or -Acetylcholine, GABA and/or Glycine
• Some docked to the presynaptic active zone

Question 6

Type I or asymmetrical synapse

Answer 6

Dense PSD
Spherical vesicles
Excitatory

Question 7

Type 2 or symmetrical synapse

Answer 7

Fine PSD
Flattened vesicles
Inhibitory

Question 8

Structure of the Presynaptic Active Zone

Answer 8

Docked vesicles
Exocytosis of clear vesicles
Presynaptic Grid,
      Hexagonal particle array
      Phosphotunsgtic Acid

Question 9

v-Snares

Answer 9

Synaptobrevin

Question 10

t-Snares

Answer 10

Syntaxin and SNAP25

Question 11

What cleaves Snare complexs

Answer 11

clostridial toxins (Botulinum toxins)

Question 12

Medium size dense cores vesicles

Answer 12

~70-80 nm
Contain catecholamines or serotonin
Filled at the synapse

Question 13

Large Dense core vesicles

Answer 13

> 100 nm
Contain neuropeptides and neurohormones
Formed in the cell body and transported to the synapse

Question 14

How are dense core vesicles released differently than clear vesicles

Answer 14

1) Not released at the active zone. Paracrine
2) Require more calcium, usually released by high activity (HIGH FREQUENCY)
3) Co-transmission
4) Dale’s principle

Question 15

Nicotinic acetylcholine receptor

Answer 15

• Made up of five subunits, arranged symmetrically around a central pore
• Respond to the neurotransmitter acetylcholine and nicotine
• Ionotropic

Question 16

Excitatory synapses

Answer 16

A synapse that depolarizes the membrane therefore bringing it closer to the action potential firing threshold
Erev > threshold

Question 17

Inhibitory synapse

Answer 17

A synapse that either hyperpolarizes or stabilizes the resting membrane potential preventing it from getting close to the action potential firing threshold
Erev < threshold