GPCRs 2 Flashcards
What does PKA in the heart do?
Phosphorylates VOCCs
which increases their activity
What are the effects of increased VOCC activity in the heart?
Increased calcium ion influx into the cell
increased contractility
positive inotropic effect
What does inotropy mean?
Force of contraction
What types of GPCRs are located in presynaptic neurones in the CNS and PNS?
M-opioid GPCRs
What type of G-protein are M-opioid GPCRs coupled to?
Gi
What effect do activated M-opioid receptors have on pre-synaptic neurones in the CNS and PNS?
Reduce neurotransmitter release
How do activated M-opioid receptors on pre-synaptic neurones in the CNS and PNS reduce neurotransmitter release?
Free beta-gamma subunit binds to VOCCs
inhibits calcium ion influx
What are the types of GPCRs located in the heart?
M2
B1
Where are M2 receptors in the heart located?
SA node
AV node
What is the outcome of activation of the different M2 receptors in the heart?
SA node - negative chronotropy
AV node - reduced cardiac conduction velocity
Where are B1 adrenoceptors located in the heart?
SA node
Ventricles
What is the outcome of activation of the different B1 adrenoceptors in the heart?
SA node - positive chronotropy
Ventricles - positive inotropy
What does chronotropy mean?
Heart rate
What are the types of GPCRs located in vascular smooth muscle?
A1
B2
What is the outcome of activation of A1 adrenoceptors in vascular smooth muscle?
Vasoconstriction