L19 Flashcards
Nociceptive pain
protective; response to the detection of noxious stimuli that can potentially cause tissue injury
Inflammatory pain
protective; caused by tissue damage; release of inflammatory mediators
Pathological pain
neuropathic pain
* caused by damage to the nervous system; e.g., spinal cord injury, diabetic neuropathy, multiple sclerosis
dysfunctional pain
- abnormal function of the nervous
system in the absence of damage or
inflammation
Inflammatory pain sensitisation simple
Tissue injury
↓
Production & release of a chemical soup
↓
Peripheral sensitisation to pain
↓
Central processing and sensitisation (Spinal cord)
↓
Signal sent to brain for final processing
What does PGE2 do with peripheral excitability
PGE2 increased peripheral excitability; evoked many action potentials,
* cAMP/PKA-dependent modulation of the tetrodotoxin-resistant sodium channel
Cyclooxygenase and prostaglandin synthesis
Membrane phospholipids
↓ – Phospholipase A2
Arachidonic acid
↓ –cyclooxygenase activity (COX)
Prostaglandin G2
↓ –peroxidase activity (COX)
Prostaglandin H2
↓
Prostaglandin E2
COX
Cyclooxygenase (COX)*
COX-1 stomach
COX-1 synthesises cytoprotective PGs (e.g., PGI2)→ protection on mucosal epithelium→ protection from peptic ulcer
Cox-1 Kidney
PGE2 production→ vasodilation and maintains renal blood flow
Cox-1 Platelet
production of thromboxane A2- platelet aggregation
COX1 CNS
distributed in neurons throughout the brain
COX-2 - inflam and CNS
- Can be induced by stimuli that are associated with inflammation
- CNS: restricted to parts of the CNS, e.g., spinal cord, hippocampus
What type of drugs inhibit COX
- steroids
- NSAID
- Diclofenac
- Aspirin
Diclofenac and COX
- Drug inhibits COX
- Compete with arachidonic acid for cyclooxygenase active site thereby blocking it