Autonomic and Neuromuscular Pharmacology

Question 1

What is the neuromuscular junction?

Answer 1

Synapse between efferent motor neuron and skeletal muscle

Question 2

What is the transmitter of the NMJ?

Answer 2

Acetylcholine

Question 3

Name 4 ways in which transmission across the NMJ could be inhibited.

Answer 3

1. Prevent Acetylcholine being package into vesicles
2. Prevent vesicle fusion
3. Prevent Calcium ion uptake by blocking calcium channels
4. Prevent post-synaptic nicotinic receptors being activated by using a competitive inhibitor to Ach.

Question 4

Name 2 ways in which transmission across the NMJ could be improved.

Answer 4

1. Increase the amount of calcium entering the cell and so increase the amount of acetylcholine release. This is usually done by blocking the potassium ion channels as influx of potassium ions generally curtails the influx of calcium
2. Inhibit the breakdown of acetylcholine so that it remains in the synaptic cleft for longer, so activating more nicotinic receptors on the post- synaptic muscle. This is generally done by blocking the acetylcholinesterase.

Question 5

Give one example of when it would be useful to block NMJ transmission.

Answer 5

During surgery, to paralyse the patient.

Question 6

Give one example of when it would be useful to increase transmission at NMJ.

Answer 6

To treat myasthenia gravis- weakening of the muscles.

Question 7

Name 4 ways in which transmission across the ganglion in the ANS could be inhibited.

Answer 7

1. Prevent Acetylcholine being package into vesicles
2. Prevent vesicle fusion
3. Prevent Calcium ion uptake by blocking calcium channels
4. Prevent post-synaptic nicotinic receptors being activated by using a competitive inhibitor to Ach.

Question 8

Name 2 ways in which transmission across the ganglion in the ANS could be improved.

Answer 8

1. Increase the amount of calcium entering the cell and so increase the amount of acetylcholine release. This is usually done by blocking the potassium ion channels as influx of potassium ions generally curtails the influx of calcium
2. Inhibit the breakdown of acetylcholine so that it remains in the synaptic cleft for longer, so activating more nicotinic receptors on the post- synaptic muscle. This is generally done by blocking the acetylcholinesterase

Question 9

What is used to alter the post ganglion transmission of the parasympathetic system of the ANS?

Answer 9

Agonists and Antagonists of the muscarinic receptors

Question 10

Name 4 ways in which post ganglion transmission of the sympathetic pathway of the ANS can be inhibited.

Answer 10

1. Block the enzymes responsible for Noradrenaline production
2. Prevent the Noradrenaline being packaged into vesicles
3. Introduce a fake transmitter which is packaged into vesicles and released but will not activate the adrenergic receptors.
4. Activate presynaptic auto receptors which inhibit calcium uptake so preventing calcium dependent exocytosis of noradrenaline.