1
Q
What are the 3 isoforms of Nitric Oxide Synthase?
A
- nNOS
- iNOS
- eNOS
2
Q
Where is NOS located and what is it activated by?
A
vascular endothelium; Ca++-CAM
3
Q
where is eNOS found?
A
Endothelial cells of the vasculature
4
Q
Where is guanylate cyclase found?
A
Vascular smooth muscle
5
Q
How does NO activate Protein kinase G (cGKI)?
A
NO binds to heme iron prosthetic group in guanylate cyclase which stimulates the production of cGMP and activates protein kinase G
6
Q
How does protein kinase G relax smooth muscle?
A
- Inhibition of L-type Ca channels (Cav1.2)
- Stimulation of Ca activated K channels (BKCa)
- Decreased MLC phosphorylation (Myosin phosphatase 1)
- Enhanced Ca uptake into ER (phospholamban)
7
Q
What limits the duration of treatment of Nitroprusside?
A
Buildup of CN- (cyanide)
8
Q
Where is prostacyclin (PGI2) produced?
A
In endothelium
9
Q
What drug class is used to treat pulmonary arterial HTN?
A
PGI2 analogs
10
Q
Where is PDE5 expressed?
A
- Vascular smooth muscle of the lungs
- Corpus cavernosum (penis)
