presynaptic blockers

Question 1

How does hemicholium work?

Answer 1

Blocks synaptic transmission if synapse is activating at high frequency, where it would run out of neurotransmitter. Blocks choline uptake which is the rate-limiting step in the synthesis of ACh and thus it decreases the synthesis.

Question 2

How does botulinum toxin act and what is its use?

Answer 2

Blocks release of ACh by interfering with docking mechanism for vesicle, and interfering 𝐶𝑎2+ activation. Thought to work at about 10 molecules per end plate to produce a complete block. Therefore need very few molecules to produce complete paralysis. No antidote. Normally fatal. Used in botox.

Question 3

What type of antibiotic is streptomycin and how does it act in nerve transmission?

Answer 3

Aminogylcoside. Interfere with 𝐶𝑎2+ activation. Many sick patients take antibiotics, so have weaker synaptic transmission. Competitive blockers are used in general anaesthesia, further reduces synaptic transmission