Opioid & non-opioid analgesics Flashcards
Identify the process by which a nociceptor converts a chemical stimulus into an action potential.
a. transmission
b. transduction
c. perception
d. modulation
b. transduction
Transduction occurs when a
chemical, mechanical, or thermal stimulus is sensed by a nociceptor and converted into an action potential
Transmission occurs when
the afferent pain signal travels from the peripheral nervous system to the central nervous system via a 3-neuron pathway
Modulation is when the
pain signal is modified (inhibited or augmented) as it advances towards the cerebral cortex
Perception is when the
pain signal is processed and “perceived” in the cerebral cortex and limbic system
Nociception is divided into four processes including
transmission
transduction
modulation
perception
A-delta fibers transmit
“fast pain” that is sharp and well-localized
C-fibers transmit
“slow pain” that is dull and poorly localized
Inflammation also contributes to
reduced threshold to pain stimulus (allodynia)
increased response to pain stimulus (hyperalgesia)
Drugs that target transduction include
NSAIDs
LAs
steroids
antihistamines
opioids
What is a first order neuron
periphery to dorsal horn
what is a second-order neuron?
dorsal horn to thalamus
What is a third-order neuron?
thalamus to cerebral cortex
Drugs that target transmission include
local anesthetics
Perception means
how we “feel” about pain
Drugs that target perception include
general anesthetics
opioids
alpha-2 agonists
The most important site of modulation is
the substantia gelatinosa in the dorsal horn (rexed lamina 2 & 3)
Pain is inhibited when
spinal neurons release GABA & glycine (inhibitor neurotransmitters)
2. the descending pain pathway release NE, serotonin, and endorphins
Pain is augmented by
wind-up
central sensitization
Drugs that target modulation include
neuraxial opioids
NMDA antagonists
alpha 2 agonists
AchE inhibitors
SSRIs
SNRIs