No and Gasses Flashcards
NO production
Produced by nitric oxide synthase from L-arginine and O2
endothelial-derived relaxing factor
The first name of NO
eNOS
constitutive
-endothelial cells
-platelets
-mast cells
-everywhere
nNOS
constitutive
-Neurons (CNS and PNS)
-mast cells
-nucleus of endothelial cells
iNOS
inducible
-macrophages
-neutrophils
-SM
-mast cells
-endothelial cells
Nitric oxide pathway
- Ach/ bradykinin / SubP receptor
- increased intracellular Ca2+
- calcium calmodulin complex forms
4.activates NOS - NO activates guanylate cyclase
- makes cGMP to cause relaxation
NO alternate pathway
1.sheer stress on cells
2.direct NOS activation
3.NO activates guanylate cyclase
6. cGMP causes relaxation
cGMP effects
-bind ion channels
-activates protein kinases (PKG)
leads to biological effect
-phophodiesterases (PDE)
NO independent effects
-Binds heme enzymes like cytochrome oxidases
-binds thiol groups
-deamination of DNA bases
cGMP deactivation
by PDE5
NO inactivation
-heme binding
-forming nitrate and nitrite
-forming peroxynitrite
NO vascular effects
Mainly via eNOS
-tonically active in resistance vessels to dilate them decreasing peripheral resistance/pressure
-inhibits clotting
NO CNS effects
NMDA receptor activation triggers NO
-important for learning and memory
-Neurotransmitter
NO PNS effects
-neurogenic vasodilation
-effects GI, rest. genitourinary functions
-ANS SM control
NO endocrine effects
-reproductive
-aggression
-feeding
