Barker's lectures

Question 1

Referred pain

Answer 1

usual distribution of pain with myocardial ischemia

Right side, jaw, epigastrium, back

Question 2

Visceral pain

Answer 2

squeezing

Question 3

Temperature sensitive

Answer 3

Peripheral receptors

Transient receptor potential cation channel (TRP)

TRPV (vanilloid)= heat, Spice
TRPM (melastatin)=cold

Question 4

Acid sensitive

Answer 4

Peripheral receptors

Acid sensing ion channel

Activated by H+
Conduct Na+

Question 5

Chemical irritant sensitive

Answer 5

Peripheral receptors

Histamine
Bradykinin

released in peripheral areas

Question 6

AB fibers

Answer 6

Non-noxious

Touch, pressure

Innervate the skin

Faster (35-75m/s)

Question 7

Adelta fiber

Answer 7

Pain,cold: conduction of pain

Myelinated

Fast (2-35 m/s)

“First pain”, reflex arc

Sharp, prickly

Question 8

C-fibers

Answer 8

Pain, temp, touch, pressure, itch

Unmyelinated

Slow (0.5-2 m/s)

“Second pain”

Dull, aching

Question 9

Substance P

Answer 9

Vasodilation

Degranulation of mast cells

Release of histamine

Inflammation of prostaglandins

Increase expression of pain receptors: sensitization

Question 10

Neuropathic pain sensitization

Answer 10

Nerve injury–>Peripheral nerve degeneration–>spontaneous afferent activity–> spinal sensitization

Spontaneous afferent activity–> spontaneous dysesthesias (shooting, burning)

Spinal sensitization–> spontaneous dysesthesia–>allodynia (light touch hurts)

AB afferent fibers–> allodynia (light touch hurts)

INCREASED AMPA AND NMDA EXPRESSION AND SENSITIVITY

Question 11

Spontaneous afferent activity

Answer 11

possibly enhanced expression of sodium channel subtypes contributing to:

enhanced cellular excitability

generation of ectopic action potentials

Question 12

High expression of opioid receptors in the brain stem along the descending pathway

Answer 12

Endogenous opioid stimulate descending pathways

Question 13

Temporal features

Answer 13

onset, duration, course, pattern

Question 14

Intensity

Answer 14

average, least, worst, current pain

Question 15

Location

Answer 15

focal, multifocal, generalized, referred, superficial, deep

Question 16

Quality

Answer 16

Inflammatory: throbbing, pulsating

Neuropathic: stabbing, shooting, burning, tingling

Visceral: squeezing

Question 17

Periphery

Answer 17

signal is conducted into the spinal cord and the signal is processed and the information is sent in an ascending input up to the brain for processing and then sent back down known as descending modulation to help control in the spinal cord the action of the afferent neuron that is bringing information into spinal cord

Question 18

Periphery

Answer 18

1. Activation of the peripheral nervous system
2. Transmission
3. Activation of CNS at spinal cord
4. Ascending input
5. Transmission of the pain signal to the brain
6. Sent down descending
7. activation of CNS at spinal cord

Question 19

Nerve transmission from the periphery to the spinal cord involved many different ion channels

Answer 19

afferent neuron sends signal towards spinal cord

along the axon Na and K channels are responsible for conduction action potential

Na1.8 important channel of the conduction of pain signals

In the spinal cord there is a release of glutamate plays an important role for conduction of pain

AMPA and NMDA

Then sends this signal onto the brain

Question 20

Descending pathway information is sent back down

Answer 20

MU opioid receptor expression

1. Brain: alter mood, produce sedation, reduce emotional reaction
2. Brainstem: Increase activity of descending fibers
3. Spinal cord: inhibit vesicle release, hyperpolarize postsynaptic membrane
4. Periphery: reduce activation of primary afferent, modulate immune activity