pharmacology of pain lecture 1

Question 1

a(delta fibres)

Answer 1

lightly myelinated
medium diameter
nociception (mech, thermal, chemical)

Question 2

c fibres

Answer 2

unmyelinated
small diameter
nociception (mech, thermal, chemical)

Question 3

what does the spinoreticulothalamic tract do

Answer 3

limbic affective

motivational aspect

Question 4

descending pathway how does it happen

Answer 4

sensory cortex –>
to PAG (in mid brain) –>
to nucleus raphe magnus –>
to dorsal horn

Question 5

in the descending pathway what happens at the dorsal horn

Answer 5

5-HT is released on to the neuron being regulated causing enkephalin to be released
inhibiting excitation of the second order neuron using GABA

Question 6

what molecules increase excitability and peripheral sensitization

Answer 6

5-HT
bradykinin 
short peptides (9aa)
prostagladins 
arachidonic acid

Question 7

what is substance p

Answer 7

neuropeptide, which increases release of 5-HT

Question 8

what is cGRP

Answer 8

neuropeptide 37aa
calcitonin family
it increases the life span of sub p

Question 9

what does NGF do to c fibres

Answer 9

increases activity
chemosensitivity
and peptide content

Question 10

what does NGF cause

Answer 10

axonal growth during development and nociceptive pathways

regulation of gene expression (ion channels, receptors)

Question 11

what is NGF and where is it produced

Answer 11

cytokine like mediator

produced by peripheral tissues particularly in inflammation

Question 12

what does NGF act on for indirect sensitivity

Answer 12

acts on kinase linked receptor TRKA on nociceptive afferent neuron