Pain psychobiology/pharmacology Flashcards
passive, direct transmission system from peripheral receptors to the cortex
nociceptive pain
Examples of nociceptive pain
acute trauma, arthritis, and tumor invasion
Acute pain starts in
the periphery, is relayed to the spinal cord, and then passes up to the brain where it produces a negative reaction
Pain producing stimuli are detected by
specialized afferent neurons called nociceptors
free nerve endings that respond to a broad range of physical and chemical stimuli at intensities that can cause damage
nociceptors
Which pain fibers send the signal to the dorsal horn of the spinal cord by way of the dorsal root ganglion?
Aδ and C
Which pain fibers are myelinated axons that quickly send the first sharp signals of pain?
Aδ
Which unmyelinated pain fibers send a slower dull pain signal; major player in chronic pain?
C fibers
nociceptive afferent nerve fibbers synapse to neurons that cross to the contralateral side of the brain
Spinal cord dorsal horn
After crossing the dorsal horn, the ascending pain signal can be modified by
descending fibers or from simultaneous activity by non pain neurons
Dampen the pain Signal in the gate theory of pain
AB fibers
This type of pain allows the subject to become aware of the location of the pain and answer the question, where does it hurt? Signal travels up the spinothalamic tract, synapses in the lateral thalamus and proceeds to the somatosensory cortex
Sensory discriminative domain
Signals communicate the intensity of the sensation and answer the question, “how much does it hurt?”.
Affective-motivational domain
This explains the natural occurrence of depression, hyperfocus, and anxiety we see with patients in pain.
The affective-motivational domain end in the cerebral cortex
a term used to describe rare genetic conditions in which people lack the ability to sense pain.
Congenital Insensitivity to pain
No A-delta and C fibers
Frank Congenital Insensitivity to Pain
These people feel pain, but are not motivated to do anything about it. Normal peripheral nerves but have a central impairment of affective-motivational component
Congenital indifference to pain
This is an autosomal recessive disorder; inability to incorporate growth factor into nerve cells. Has no pain fibers.
Congenital Insensitivity to Pain with Anhidrosis
How is pain tolerance affected in those with schizophrenia?
Increased pain tolerance
Pain pathways are
Descending (top down control of pain)
kappa opioid receptor is thought to play a role in
pain and depressive symptoms
Activation of the kappa opioid receptor can provide some
analgesia
Antagonism of the kappa opioid receptor can provide
relief from some depressive symptoms associated with opioid withdrawal
The delta opioid receptor is thought to play a role
in modulating chronic pain and is activated by enkephalins
Antagonizing delta opioid receptors may play
an active role in pain relief
The Mu receptor’s activation is required for
most analgesics
The affinity that a medication has for the mu receptor correlates with
its potency as an analgesic
What binds with the mu receptor and acts as the quintessential antagonist for it, blocks activation, and can precipitate withdrawal
Naloxone
Which receptor is most closely associated with euphoria and abuse
mu
Evidence for long-term use of opioids for nonmalignant chronic pain is
almost nonexistent
Why is dose escalation a bad thing?
Tolerance to analgesic and euphoric effects develops quickly, which requires dose escalation. Tolerance for respiratory depression develops slower, which explains why dose escalation by well-meaning prescribers can precipitate an overdose
Long term use of opioids leading to increased sensitivity to painful stimuli is called
opioid hyperalgesia
This sensitivity is induced by morphine and is caused by an inflammatory response (cytokines) mediated by spinal microglia; possibly having acute pain transition into chronic pain.
Persistent pain sensitivity
Athletes, performing artists, soldiers wounded in battle some women in labor may have a stimulated opioid dependent pathway to inhibit pain or an endocannabinoid accumulation in the PAG. This is called.
Stress induced analgesia
This treatment causes a decrease awareness in pain perception brain areas associated with endogenous opioids. Increased activity involved with top down suppression of pain.
Placebos
