receptor regulation

Question 1

What are the ways a receptor can be regulated?

Answer 1

receptor level

post receptor mechanism

Question 2

What are the ways that a receptor can be regulated at the receptor level?

Answer 2

persistant agonist stimulation

Chronic deprivation of recptor excitation

Question 3

What happens to the receptor if it has persistant agonist stimulation?

Answer 3

subsensitivity - down regulation of receptor number or density

they are internalized by the cell to lysosomes

Question 4

What happens to a receptor when it has chronic deprivation of receptor excitation?

Answer 4

supersensitivity - upregulation of receptor number or density

Question 5

What does not alter receptor affinity or density?

Answer 5

A brief exposure to an agonist or a reversible competitive antagonist

Question 6

What are post receptor mechanism for receptor regulation?

Answer 6

densitization- a rapid decrease in responsivness (tachyphylaxsis)

refractoriness - loss of theurapeutic efficacy

tolerance- gradual decrese in respnsivness

drug resistance-loss aniibacterial efficacy of drug

Question 7

What are the ways a receptor can be densisitized?

Answer 7

phosphorylation

dephosporylation

Question 8

What are the different types of phosphorylation?

Answer 8

Homologous

heterologous

Question 9

What is homologous phosphorylation?

Answer 9

agonist dependent

Gprotien coupled receptor kinases required

only phosphorylate agonist occupied receptors this causes minimal desensitiztion but increases arreatin affinity

arrestin binding causes max desinsitization

Question 10

What heterologous phosphorylation?

Answer 10

agonist independent-
phosphorylates those stimulated by agonist receptor and those that are not

only40-50% desensitization