PHAR232 - Weeks 3 & 4 Flashcards
Do heart beta receptors decrease with age?
Yes
What are the 2 primary groups of receptors?
- Ionotropic receptors
- Metabotropic receptors
Are ionotropic receptors fast or slow?
Fast (milliseconds)
Name 3 examples of ligand-gated ion channels (ionotropic)
- Nicotinic ACh receptor
- GABA-A receptor
- NMDA glutamate receptor
How many ACh ions are required to bind to open up a nicotinic ACh receptor?
2
What nutritional compound is bound to stabilize NMDA glutamate receptors and must leave before glutamate can bind?
MG2+
What are the 2 main positive ions for stimulatory influx?
Na+
Ca2+
(depolarisation)
What are the key INHIBITORY ions for ligand-gated ion channels?
K+ = (positive efflux) e.g. hyperpolarism
Cl- (negative influx)
Making the cell more negative
What is the GOAL of the ligand-gated ion channels?
To change membrane potential
- negative (hyperpolarise) or positive (depolarise)
What are some examples of G-protein coupled receptors?
0 Noradrenaline,
- Serotonin
- Muscarinic ACh
- Opioid
- GABA-B
- Histamine
- Prostaglandins
How many transmembrane domains do a GPCR have?
7
What is a newer GPRC type?
Protease-activated receptors (PARs)
List Protease-activated receptors (PARs) attributes
- Tehtered ligand
- Looks like GPCR
- Interacts with GPCR
- REGULATION VIA PHOSPHORYLATION
- 1 use only
- AGONIST IS PART OF THE RECEPTOR
- Implicated as a ‘warning system’ for diseases
What is the newer GPCR that is activated by H+ ions?
proton-sensing
What’s the name of GPCR that are activated by specific lipids? e.g. lysophosphatidylcholine
lysolipid-sensitive GPCR
- associated with cancers
- Inflammation
- Apoptosis
What is a GPCR that is highly associated with the parathyroid hormone?
calcium-sensing receptors
What are key physical aspects of the GPCR?
- Heterotrimeric: 3 individual proteins in combination (alpha, beta, gamma)
- ## 7 transmembraine domains
When speaking of a beta subtype - are we talking about 1. the ion channels or 2. the G-protein subtype?
- the g-protein subtype
What are key things that define an alpha subunit?
- GTPases
- THEY ARE AN ENZYME
- alpha subunit a rest has GFP bound to it
- at rest unit = alpha + beta + gamma
- Activation = enzyme receptor changes shape for interaction
Alpha subunit shape change causes ________ to be DROPPED and _______ to be taken up?
GDP = DROPPED
GTP = INTAKE - active
What ACTIVATES the alpha subunit?
alpha subunit + GTP = active subunit