Receptor mechanism I

Question 1

What does acetylcholine do to cardiac contraction?

Answer 1

Acetylcholine reduces cardiac contraction

Question 2

What does acetylcholine do to smooth muscle contraction?

Answer 2

Increases contraction of smooth muscles

Question 3

What is nicotinic cholinoreceptor activated by?

Answer 3

Activated by acetylcholine

Question 4

What is 5HT3 activated by?

Answer 4

Activated by 5-HT

Question 5

What is GABAA activated by?

Answer 5

GABAA activated by GABA

Question 6

What is glycine receptor activated by?

Answer 6

Glycine

Question 7

What ions do nicotinic receptors bind to and what happens to the membrane potential as a result?

Answer 7

The ions which bind are Na/Ca and causes the membrane to depolarise

Question 8

What ions do 5HT3 receptors bind to and what happens to the membrane potential as a result?

Answer 8

The ions which bind are Na/Ca and causes the membrane to depolarise

Question 9

What ions do GABAA receptors bind to and what happens to the membrane potential as a result?

Answer 9

The ions which bind are Cl and cause the membrane to hyperpolarise.

Question 10

What ions do Glycine receptors bind to and what happens to the membrane potential as a result?

Answer 10

The ions which bind are Cl and cause the membrane to hyperpolarise.

Question 11

Structure of Ligand gated ion channel receptor:

What site does a ligand gated ion channel receptor have?

Answer 11

Has a ligand binding site

Question 12

Structure of Ligand gated ion channel receptor:

How many proteins is a ligand gated ion channel receptor made up of?

Answer 12

Made up of 5 proteins

Question 13

Structure of Ligand gated ion channel receptor:

How many Transmembrane domains does each protein have?

Answer 13

Each protein has 4 transmembrane domains

Question 14

Structure of Ligand gated ion channel receptor:

What do the amino acids in TM2 contribute to?

Answer 14

Amino acids in TM2 contribute to aqueous ionic pathway

Question 15

What happens as soon as an agonist binds to a receptor?

Answer 15

Get a molecular kink

Ion pathway opens instantaneously

Question 16

How many agonists needed for full opening of LGICR?

Answer 16

2 agonists needed for full opening of ion channels in LGICR

Question 17

What are the 2 superfamilies of nicotinic acetylcholine receptors?

Answer 17

N1 or NM in skeletal muscles end plates

N2 or NN in CNS and autonomic ganglia

Question 18

What does stimulation of nAChr in skeletal muscles do?

Answer 18

Stimulation of nAChr in skeletal muscles contracts muscle quickly

Question 19

What is the EJP?

Answer 19

Excitatory junction potential which is produced by influx of Na+ through nAChr

Question 20

Composition of N1 AChR’s

Answer 20

α1-ε-α1-β1-δ

Question 21

Composition of muscle nicotinic AChr’s

Answer 21

α1-ϒ-α1-β1-δ

Question 22

Composition of N2 AChr’s

Answer 22

α2-α8 and β2-β4

Question 23

What happens to muscle nAChr’s in myasthesia gravis?

Answer 23

Muscle nAChr’s become degraded

Question 24

What type of disease is myasthesia gravis?

Answer 24

Autoimmune disease

Question 25

What does myasthesia gravis target and therefore what are unaffected?

Answer 25

Target the α1 subunit

Thus NN AChr’s unaffected

Question 26

What are the symptoms presented from patients suffering from myasthesia gravis?

Answer 26

Muscle weakness

Question 27

What are missing with people suffering from myasthesia gravis?

Answer 27

Mepps are missing

Question 28

What gives these mepps?

Answer 28

Acetylcholine vesicles always colliding with motor neurone all the time giving these mepps.

Question 29

What does stimulation of GABAA receptors in neurones do?

Answer 29

Inhibit activity quickly

Question 30

What are the steps that occur when GABAA in neurones are stimulated?

Answer 30

Inhibitory nerves release GABA or glycine
GABAA receptors or glycine receptors are stimulated
Aqueous ion pathway formed
Cl- allowed to enter
Result in hyperpolarisation
Activity inhibited