NSAIDs Flashcards
Examples of prostanoids + their actions
- Prostaglandins: vasodilators
- Prostacyclin (PGI2): vasodilator | prevent platelet aggregation
- Thromboxane: platelet granule > initiation of platelet aggregation | vasoconstrictor
- PGE2: good for stomach > regulation of a stomach acid
How are prostanoids produced?
Produced locally on demand from arachnoid acid
Role of prostanoids in the GI system
- PGE2: regulation of acid secretion in parietal cells
- prostacyclin: maintenance of blood flow + mucosal repair
How do prostanoids signal?
Act locally via many GPCRs
What is a consequence of imbalance of prostanoids?
Hypertension
MI
Stroke
Why is the Mediterranean diet suggested to lower incidence of CVD?
- diet is rich is fish oil
- proposed to lead to conversion of thromboxane + PGI3 (better prostanoids)
What are the two functional isoforms of cyclooxygenase enzymes?
COX-1
COX-2
Compare the haemostatic function of COX-1 + COX-2
COX-1:
- GI protection
- platelet aggregation
- vascular resistance
.
COX-2:
- renal homeostasis
- tissue repair + healing
- uterine contractions
- inhibition of platelet aggregation
Compare the pathological functions of COX-1 + COX-2
COX-1:
- chronic inflammation
- chronic pain
- hypertension
.
COX-2:
- chronic inflammation
- chronic pain
- fever
- blood vessel permeability
Compare the active sites in COX-1 + COX-2
COX-2 has a larger + more flexible binding site
What is the common mode of action of NSAIDs?
Inhibition of COX
- decrease prostaglandin, prostacyclin + thromboxane synthesis
- compete with arachidonic acid for site of COX enzymes
What are three general actions of NSAIDs?
Analgesia
Anti-inflammatory
Antipyretic
How do NSAIDs work as analgesics?
- COX inhibition
- decreases PGE2 synthesis in dorsal horn
- decrease neurotransmitter release > decrease excitability of neurone in pain relay pathway
- inhibition reduces peripheral pain fibre sensitivity
How do NSAIDs work as anti inflammatories?
- COX inhibition
- reduce production of prostaglandins released at site of injury
- reduces vasodilation + swelling
How do NSAIDs work as antipyretics?
Inhibition of hypothalamic COX-2 where cytokine induced prostaglandin synthesis is elevated > reduced temperature