pain pathways Flashcards
name the 4 types of drugs that act on nociception in the peripheral afferent fibers
opioids
LA
cox2 inhibitors, nsaids, aspirin
ketamine
drugs acting on the dorsal horn
LA cox2 inhibitors, nsaids, aspirin ketamine opioids alpha 2 agonist
What is the path inside the PAG naming receptors that cause disinhibition and activation descending pain pathways of the raphe and LC
-2nd order neuron from dorsal horn release glutamate
-glutamate binds to NMDA receptor on enkephalin -
interneuron/ enkephalin released
-enkephalin binds to Mu/Gi receptor on GABA interneuron stopping release of GABA
-Glutamatergic neuron of descending disinhibited/fires down to raphe and LC
sodium gates channels cause erythromelalgia (burning pain)
gain of function mutation
results in congenital pain insensitivity
loss of function mutation
spinothalamic projects to
somatosensory cortex
trigeminothalmic tract projects to
somatosensory cortex
spinoemotional tract projects to
thalamus
association cortex
limbic system
higher order of processing of pain
spinoreticular tract projects to
RAS/locus coeruleus(pons)/Raphe magnus (medulla)
spinomesencephalic tract projects to
PAG
descending input from the amygdala (fear anxiety) tract projects to
hypothalamus / PAG
pituitary ( secretes ACTH & B endorphin)
Sites of action Local anesthetics
o Nociception afferent nerve fiber terminals
o First order neurons
o Dorsal horn of spinal cord
o Brain
o endogenous = NE (came from locus coeruleus)
o Descending inhibitory circuits PAG, Locus Coeruleus, Raphe Magnus
o Nociception afferent nerve fiber terminals
o First order neurons
o Dorsal horn of spinal cord
Sites of action NSAIDs, COX2 inhibitors, ASA
Nociception afferent nerve fiber terminals
o Dorsal horn of spinal cord
o Brain
Sites of action Opioids
Nociception afferent nerve fiber terminals
o Dorsal horn of spinal cord
o Brain
Sites of action Alpha2 agonists (dexmedetomidine)
o endogenous = NE (came from locus coeruleus)
