T1 L1: Synaptic transmission

Question 1

What are some properties of electrical synapses?

Answer 1

Compared to Chemical ones,

• They’re simpler in structure and function
• Faster
• Passive
• Bidirectional
• Common during development

Question 2

What are some properties of chemical synapses?

Answer 2

• Cant be amplified

- Complex

Question 3

Which type of chemical synapse is specialised for integration?

Answer 3

Axoaxonic

Question 4

What are the 2 membrane differentiations of a synapse?

Answer 4

The active zone and postsynaptic density

Question 5

What is the response of a direct excitatory or inhibitory neurotransmission?

Answer 5

Depolarisation or hyperpolarisation of the next cell

Question 6

What are the different responses to neuromodulation?

Answer 6

Altered presynaptic cell ability to release more neurotransmitter or the postsynaptic cell’s ability to respond

(Changes in response or release)

Question 7

How do you define a neurotransmitter?

Answer 7

• Synthesised in the neuron
• Present in the presynaptic terminal
• When administered exogenously it mimics the action of the endogenously released transmitter
• A specific mechanism removes it from the synaptic cleft

Question 8

What does synapsin do?

Answer 8

Anchors vesicles above the active zone to the cytoskeleton of cells

Question 9

What molecule phosphorylates synapsin?

Answer 9

Calcium calmodulin activated kinase II (CaMkII)

Question 10

Describe the process that causes vesicles to be released from the synapse

Answer 10

Vesicle docks and the SNARE complexes form to pull membranes together. Ca2+ enters and binds to synaptotagmin. That complex then catalyses membrane fusion by binding to the SNARE complex and the plasma membrane so the contents of the vesicle is released

Question 11

What does the SNARE complex do?

Answer 11

Docks vesicles to the plasma membrane in a synapse

Question 12

What effect do clostridial toxins have on the body molecularly?

Answer 12

They cleave SNARE proteins

Question 13

What does Botulinum toxin do?

Answer 13

Prevents the releases of ACh causing paralysis

Question 14

What does Tetanus toxin do?

Answer 14

Prevents release of Glycine and GABA at inhibitory neurons causing constant contraction

Question 15

What are Congenital myasthenic syndromes?

Answer 15

A group of conditions causing muscle weakness (myasthenia) that worsens with physical exertion

Question 16

What does Latrotoxin work physiologically?

Answer 16

Triggers vesicle fusion causing uncontrolled nerve depolarization, increasing intracellular calcium and stimulating uncontrolled exocytosis and release of neurotransmitters

Question 17

What is LEMS (Lambert-Eaton myasthenic syndrome)?

Answer 17

An autoimmune disease that attacks presynaptic Ca2+ channels

Question 18

What does impaired trans-synaptic signalling cause?

Answer 18

Cognitive disorders

Question 19

What type of gradient powers vesicular transporters?

Answer 19

A proton gradient (ATPase proton pumps load vesicles with H+ making vesicles acidic compared to the neutral pH of the cytoplasm)

Question 20

What type of gradient powers plasma membrane transporters?

Answer 20

Electrochemical gradient ( [Na+] higher outside / [K+] higher inside)

Question 21

Describe how a neural threesome enhances or inhibits neural activity

Answer 21

Astrocytes wrap around synapses. Neurones signal between each other by releasing neurotransmitters that the astrocyte can also take up causing an increase in intracellular Ca+ in the astrocyte

Question 22

What is reactive gliosis?

Answer 22

Describes a response of astrocytes in situations such as brain or spinal cord trauma, epilepsy, stroke, or neurodegenerative diseases. Leads to scars and inflammation