Pain Flashcards
(25 cards)
What are prostaglandins and their role in pain?
They are produced in response to skin damage and swelling; they sensitize nerve endings, making them more likely to send pain signals to the brain.
What are Aδ fibres responsible for?
They are highly myelinated and convey mechanical pain quickly and precisely — responsible for early pain.
What are C fibres responsible for?
They are unmyelinated and convey various types of pain slowly and less precisely — responsible for late pain.
Name 3 types of C fibre sensitivities.
Mechanical extremes, pungent irritants (e.g. mustard oils), and extremes of temperature/acid/capsaicin.
What neurotransmitter is associated with extreme pain in somatosensory pathways?
Substance P.
Where is physical pain sensation processed?
Primary Somatosensory Cortex.
Where is the emotional unpleasantness of pain processed?
Anterior Cingulate Cortex.
Name non-drug approaches to pain suppression.
PAG stimulation, stress, placebo effect, acupuncture.
How does placebo cream reduce pain?
Activates the dorsolateral prefrontal cortex → activates PAG → triggers descending analgesia circuit.
How does capsaicin reduce pain?
It depletes Substance P from sensory terminals, providing local analgesia.
How do NSAIDs reduce pain?
Inhibit COX-1/2 enzymes → reduces prostaglandin production
Give examples of NSAIDs.
Aspirin, Ibuprofen, COX-2 inhibitors.
Major side effects of NSAIDs?
Stomach issues (COX-1 protects stomach lining), impaired clotting (aspirin).
How does paracetamol act?
Forms AM404, an agonist of TRPV1 and CB1 receptors — reduces pain through cannabinoid pathways.
Name 3 commonly used opiates.
Morphine, codeine, heroin.
What do opiates mimic?
Endorphins (endogenous opioids).
List 3 short-term effects of opiates.
Pain relief, sleep induction, cough suppression.
Where are opioid receptors located?
Brain (e.g., PAG, VTA, preoptic area) and peripheral organ
Symptoms of heroin withdrawal?
Sweating, vomiting, diarrhea, shivering, restlessness.
How do opiates cause addiction?
Inhibit GABA in VTA → increased dopamine in nucleus accumbens.
What are THC and CBD?
Active compounds in cannabis; THC is a CB1/CB2 agonist, CBD is a CB1 antagonist.
Short-term recreational effects of cannabis?
Distorted time, heightened senses, euphoria, dissociation.
Medicinal uses of cannabis?
Reduces nausea, increases appetite, blocks seizures, decreases glaucoma severity, relieves pain.
What is Depolarisation-induced Suppression of Inhibition (DSI)?
Cannabis-induced suppression of GABA release → increased neuron firing in hippocampus.
