Lecture 9

Question 1

Examples of drugs acting on central nervous system?

Answer 1

-Convultants e.g Strychine Tetanaus toxin
-Myotonolytics Diazepam e.g Baclofen
-Anti-Epileptics
-Anti-Parkinsonians

Question 2

Examples of drugs acting on the neuromuscular junction?

Answer 2

-Muscle Relaxants
-Dantrolene EC-coupling
-Anti-AChE drugs
-Toxins

Question 3

What is alpha-Bungarotoxin?

Answer 3

-It is a high toxic peptide that inhibits the binding of acetylcholine (ACh) to the acetylcholine receptor (AChR).
-It does this by binding to the NMJ nAChr (nicotine acetylcholine receptor)
-This binding can results in paralysis and respiratory failure

Question 4

Action potential in the motor neurons cause what?

Answer 4

Exocytosis of acetylcholine containing synaptic vesicles.

Question 5

Where does acetylcholine bind to its receptors?

Answer 5

In the plasma membrane of the junctional folds of the skeletal muscle cells

Question 6

How is excess acetylcholine removed

Answer 6

With the enzyme acetylcholinesterase (AChE)

Question 7

What is action potential?

Answer 7

-It is the electrical gradient across the plasma membrane of an axon first depolarizers and repolarized the cell
-caused by the opening and closing of voltage-gated Na+ and K+ channels.

Question 8

Examples of anticholinesterases

Answer 8

-Edrophonium (Reverses NM block)
-Neostigmine (Used to diagnosis of MG)
-Pyridostigmine (Used for treatment of MG)

Question 9

Examples of neuromuscular blocking drugs?

Answer 9

-Tubocurarine
-Pancuronium
-Vecuronium
-Atracurium
-Mivacurium
-Suxamethonium

Question 10

What is MG?

Answer 10

-Mynsthenia Graves is a chronic autoimmune neuromuscular disease that causes weakness of the skeletal muscles

Question 11

2 types of neuromuscular blocking drugs?

Answer 11

-Presynaptic
-Postsynaptic

Question 12

Types of presynaptic agents?

Answer 12

1. Inhibition of ACh synthesis e.g Hemicholine which inhibits choline transport
2. Inhibition of ACh release e.g Botulinum toxin which inhibits exocytosis of synaptic vessel

Question 13

Postsynaptic agents?

Answer 13

-Used for clinical paralysis during anesthesia
-E.g Tubocurarine, Pancuronium, Atracurium, Suxamethonium

Question 14

What is clinical spasticity?

Answer 14

It is when the flexor muscle spasms

Question 15

Function of proprioceotors?

Answer 15

They measure the position of joints and length of muscle
-An important class is called Muscle spindles

Question 16

Types of reflexes?

Answer 16

1. monosynaptic
2. Polysynaptic

Question 17

How can the activity of a hyperactive stretch reflex be reduced?

Answer 17

With drugs:
-Diazepam: facilitates GABA mediated presynaptic inhibition
-Baclofen: interferes with release of excitatory transmitters

Question 18

What is Dantrolene?

Answer 18

It is a drug that directly modulates excitation contraction coupling by inhibiting calcium ion release from the sarcoplasmic reticulum of skeletal muscle fibers and thereby reduces muscle strength

Question 19

What is Dantrolene used to treat?

Answer 19

-Malignant hyperthermia
-Controls increase in body temperature and muscle contractions caused by the disease.