Receptors

Question 1

What is a ligand?

Answer 1

A ligand is any molecule that binds specifically to a receptor site.

Question 2

What are the different types of intercellular signalling?

Answer 2

Paracrine - local chemical mediators
Endocrine - hormones
Synaptic - neurotransmitters

Question 3

What is a receptor?

Answer 3

A receptor is a molecule that recognises specifically a second molecule (ligand) or family of molecules and which in response to ligand binding brings about regulation of a cellular process.

Question 4

What is an antagonist?

Answer 4

A ligand may combine with a receptor site without causing activation. This type of ligand is termed an antagonist because it would oppose the actions of an agonist.

Question 5

Name 2 membrane bound receptors with integral ion channels.

Answer 5

Nicotinic acetylcholine receptor (nAChR)
Gamma amino butyric acid (GABA) receptor
Glycine receptor
Glutamate receptors (NMDA, kainate and AMPA)

Question 6

Name the three main types of membrane bound receptors.

Answer 6

Membrane bound receptors with integral ion channels (ligand gated ion channels)
Membrane bound receptors with integral enzyme activity
Membrane bound receptors which couple to effectors through transducing proteins (7TMDP)

Question 7

What is the underlying pathophysiology of myasthenia gravis?

Answer 7

An autoimmune disease targeting nACh receptors on the post-junctional membrane of the neuromuscular junction.

Question 8

GPCRs share a basic structure, describe this.

Answer 8

Single polypeptide chain (300-1200 amino acids)
7 transmembrane spanning regions
Extra cellular n terminal
Intracellular c terminal