Pain-relieving attributes of Morphine.

Pain-relieving attributes of Morphine.

Conscious perception of pain occurs after a series of nociceptive signal transduction,
transmission and processing in the respective cortex. Alterations in either transmission and
processing limit the perception of the actual pain. Pain transmission is usually conducted by
both the spinothalamic and spinocerebellar tracts. The lateral spinothalamic tract consists of
three sets of neurones; the afferent neurone which synapses with the 2 nd order neurone at the
dorsal horn of the spinal cord. This synapse point is usually a good point for pain modulation.
The 2 nd order neurone ends at the thalamus where the succeeding neurone directs the impulse
to the appropriate cortex. Synapses involve neurotransmitter release by the presynaptic cleft
and uptake by receptors in the postsynaptic cleft. Other receptors also have actions on their
neighbouring receptors (He et al., 2018).

Fig 1.3 The Synapse. Impulse transmission is dependent on the release and uptake of
neurotransmitters which can be manipulated for pain modulation. (He et al., 2018).
This arrangement offers a strategic point for pain modulation and elimination by
manipulating the transmission of the impulse. Morphine is an opioid with its mechanism of

Invasive Ductal Carcinoma 7
action being heavily pegged and dependant on opioid receptors. These receptors are in three
types, kappa, mu and delta. They are spread within the pain transmission pathway. The delta
type is located in the digestive tract and the spinal cord while kappa is located in the
diencephalon, brain stem and spinal cord with mu receptor being found in the brain stem and
the thalamus. The analgesic effects of morphine are achieved by activating these receptors
which leads to descending inhibitory inhibitions following inhibition of GABA interneurons
(Sun et al., 2017). Additionally, activated opioid receptors lead to reduced neurotransmitter
release at the substantial gelatinosa which is the synapse point between afferent neurone and
the second-order neurone.