pain Flashcards
What three things can activate the TRPV1 channel
acid
capsaicin
temperature
what substances do nocioceptors release when activated
substance P
CGRP
which mediators activate nocioceptors
bradykinin serotonin histamine Prostaglandins cytokines
how does pain hypersensitivity or allodynia occur
transcription mediated cytokine and GFs increase the production of receptors, ion channels and NTs –> exaggerated responses
difference between A delta and C fibres
A delta - sharp, acute, localised pain, thermal pain
C fibres - slow pain aching, throbbing, chemical pain
what is the main NT involved in nocioception
glutamate
what NT is inhibitory for nocioception
GABA
what are the 2 main NTs activated by glutamate in nocioception
AMPA
NMDA
what is the difference in activation of AMPA and NMDA in nocioception
NMDA only activated in situations where there is prolonged pain/stimulus
explain the activation of the NMDA receptor
Mg plug is displaced causing cell remodelling and c-fos gene expssion –> causing spinal cord sensitisation
what drug class are endorphins
opoid
what endogenous molecule is produced to try and inhibit pain feeling
endorphins
where is the primary site of action of opiods and how do they work
spinal cord - act pre-synaptically to decrease NT release and post-synaptically to hyperpolarise the dorsal root neurons
what kind of fibres are descending pain fibres that interact with nocioception
noradrenergic and 5-HT3
which receptor is targetted in neuropathic pain
N type Voltage gated Ca channel receptor
which parts of the brain are involved in nocioception
superior colliculus
periaqueductal grey matter (PAG)
how does the HR and BP increase with pain
through complex interaction between the cardiovascular centre and the PAG
how can someone experience no pain
absence of sodium channel
if you have the stargazer gene = what are you susceptible to
chronic pain
side effects of opoids
ventilatory depression drowsiness/sedation postop nausea and vomiting pruitis urinary retention constipation
what is the theory behind multimodal analgesia
target pain transmission at multiple sites and reduce opoid requirement
what is the theory behind pre-emptive analgesia
attenuate injury and the neuroplastic response
