Pain Flashcards
neuropathic pain - peripheral nerve damage
Phantom limb pain – sensation of pain in an amputated limb, long after its removal
• Infectious diseases (e.g. HIV, leprosy and hepatitis)
• Diabetic neuropathy
• Trigeminal neuralgia
• Postherpetic neuralgia
analgesics approaches
inhibiting sensitisation and decreasing neuronal excitability
non-steroidal anti-inflammatory drugs
peripheral action: inhibiting COX enzymes and therefore the production of prostaglandins (PGs) –> less nociceptor sensitisation ( return to normal state) = less pain
most inhibit COX-I and COX-2 –> future hopefully just COX-2 less side effects
Aspirin
t enters the active site and acetylates a serine at position 530, which irreversibly inactivates COX, an action that explains certain long-lasting actions of aspirin
COX-1
constitutive and expressed in many tissues,
COX-2
induced in inflammatory cells when they are activated by, for example,
cytokines such as TNF-α during inflammation
- however, some are in tissues
inhibition COX-I
responsible for unwanted side effects
inhibition COX-II
anti-inflammatory, analgesic effect
what is pain?
an unpleasant sensory and emotional experience associated with actual or potential tissue damage or described in terms of such damage
nociception
the neural process of encoding noxious stimuli
nocicpetors what
thinly mylenated a-delta or unmylenated C fibres
nociceptors - where located
• Cell bodies located in DRG (dorsal root ganglia) or in TG for the head (trigeminal ganglia)
ion channels in nocicpeptor function
- If receptor potential depolarization is great enough, NaVs activated
- AP propagation to presynaptic terminals in spinal cord results in opening of CaVs
- Ca2+ leads to release of neurotransmitters onto postsynaptic terminals in spinal cord
pharmalogical intervention
can intervene at any step of nociceptor transduction
heat
(TrpV1
cold
TrpM8
mechanical stimuli
peizo 1/2
H+
TRPV1, ASICs
opiod
A substance producing morphine like effects that are reversed by antagonists such as naloxone , act on 4 receptors
opiate
A substance found in the opium poppy Papaver somniferum
eg codeine
