ICPP session 6-12

Question 1

GPCR action

Answer 1

1. Ligand binds at binding domain
2. Causes conformational change
3. GDP dissociates from alpha subunit and is replaced by GTP
4. beta-gamma unit and alpha subunit dissociate, alpha GTP activates effector protein (e.g adenylyl cyclase)
5. Triggers conversion of ATP-> cyclic AMP, activates protein kinase A/ phospholipase C leads to conversion of PIP2 to IP3 and DAG, which activate protein kinase C
6. GTP is hydrolysed to GDP on alpha subunit and subunits reassociate

Question 2

Intracellular receptor binding

Answer 2

Hormone binds at hormone binding site, inhibitory protein complex dissociates exposing DNA binding site

Question 3

G protein types

Answer 3

G alpha s: stimulates adenylyl cyclase
G alpha i: inhibits adenylyl cyclase
G alpha q: stimulates phospholipase C

Question 4

Types of G protein coupled receptors

Answer 4

QISS QIQ
Alpha 1: alpha Q subunit, effects phospholipase C
Alpha 2: alpha I subunit, effects adenylyl cyclase
Beta 1: alpha S subunit, effects adenylyl cyclase (located in heart)
Beta 2: alpha S subunit, effects adenylyl cyclase (located in lungs)
M1: alpha Q subunit, effects phospholipase C
M2: alpha I subunit, effects adenylyl cyclase
M3: alpha Q subunit, effects phospholipase C

Question 5

Branches of autonomic nervous system (origin + types of nerves)

Answer 5

Sympathetic: originates in lateral horn of thoracic and lumbar spinal cord, short preganglionic neurone, long postganglionic neurone, ganglia located in PARAVERTEBRAL CHAIN

Parasympathetic: originates in lateral horn of medulla and sacral spinal cord, long preganglionic neurone, short post, ganglia within INNERVATED TISSUES

Question 6

Parasympathetic discharge pathological effects

Answer 6

Salivation- stimulation of salivary glands
Lacrimation- stimulation of lacrimal gland
Urination- relaxation of urethral internal sphincter muscle
Defection
GI upset- smooth muscle tone changes
Emesis- vomiting

Question 7

Drug administration methods

Answer 7

OI IT IS SIR
Oral
Intravenous
Intramuscular 
Transdermal
Inhalation
Sublingual
Subdermal
I?
Rectal