Opioid analgesics 2

Question 1

In pain pathway when pain is caused by what?

Answer 1

noxious stimulation, substance P, glutamate, and other excitatory neurotransmitters

Question 2

The pain activates which neurons?

Answer 2

Primary afferent neurons

Question 3

The primary afferent neurons enter what during pain pathway and do what?

Answer 3

Enter spinal cord where they synapse with interneurons directly onto spinothalamic tract neurons (STTs)

Question 4

what does the Neospinothalamic tract do in the pain pathway

Answer 4

The neospinothalamic tract projects to the primary sensory cortext, which alerts the individual to the presence and location of pain, the sensory-discriminative component.

Question 5

what does the paleospinothalamic tract do in the pain pathway?

Answer 5

The paleospinothalamic tract projects to limbic structures, which mediate the motivational affective response to pain.

Question 6

what does the nonopioid analgesics do in the pain pathway?

Answer 6

The nonopioid analgesics reduce the activation of primary afferent neurons via inhibition of prostaglandin synthesis

Question 7

The descending neuronal tracts are from where?

Answer 7

Periaqueductal gray (PAG) matter

Question 8

The descending neuronal tracts activates neurons that releases what?

Answer 8

1. Norepinephrine (NE)
2. Serotonin (5-hydroxytryptamine, or 5-HT)
3. Enkephalin (Enk) in the spinal cord and thereby block ascending pain transmission

Question 9

explain the function of opioid analgesics in pain pathway

Answer 9

Opioid analgesics activates the descending pathways and directly activates opioid receptord on afferent nerve terminals and on STT neurons in the spinal cord.

Question 10

The medullary neurons include serotogenic nerve which arising in the?

Answer 10

Nucleus magnus raphe (NMR)

Question 11

Medullary neurons include noradrenergic nerves arising in the?

Answer 11

Locus coeruleus (LC)

Question 12

when serotonergic and noradrenergic nerve release serotonin and norepinephrine in the spinal cord what happen?

Answer 12

They inhibit dorsal spinal neurons that transmit pain impulses to supraspinal sites

Question 13

Nerve fibers from PAG also actovates what?

Answer 13

Also activate spinal interneurons that release an endogenous opioid peptide, met-enkephalin.

Question 14

The enkephalins act?

Answer 14

1. Presynaptcaly to decrease the release of pain transmitters from the central terminations of primary afferent neurons
2. Postsynaptic receptors on spinothalamic tract neurons in the spinal cord to decrease the rostral transmission of the pain signal

Question 15

The opioid analgesics activates what?

Answer 15

Opioid analgesics activates the descending PAG, NMR, and LC neuronal pathways, and they also directly activates opioid receptors in the spinal cord.

Question 16

The activation of spinothlamic neurons in the spibnal cord is modulated by what?

Answer 16

1. Descending inhibitory pathways from the midbrain and by
2. Sensory A-beta fibers arising in peripheral tissues

Question 17

The descending inhibitory pathways from the midbrain and sensory A-beta fibers arising in peripheral tissues constitute the neurologic basis of the ?

Answer 17

Gate-control hypothesis

Question 18

Pain transmission by spinothalamic neurons can be modulated, or gated by what?

Answer 18

Inhibitory activity of other types of large fibers impinging on them

Question 19

Activation of spinothalamic neurons is also inhibited by peripheral A-Beta sensory fibers that stimulates what?

Answer 19

Release of met-enkephalin from spinal cord interneurons

Question 20

A-beta fibers mediates analgesic effects produced by several types of what? explain

Answer 20

Tissue stimulation, including acupunture and transcutaneous electrical nerve stimulation (TENS). These mechanisms explain the pain relief that may be produced by simply rubbing or massing a midly injured tissue