Analgesic, spinal

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In the spinal cord GABA can also activate the G-protein-linked GABAb receptor, also found pre- and postsynaptically. Baclofen modulation of nociceptive transmission is seen under inflammatory conditions in animals but in humans the drug appears to lack any analgesic effect. 

Acetaminophen is a centrally acting analgesic that produces analgesia by inhibiting prostaglandin production in the brain and spinal cord. It is an effective and inexpensive analgesic with a favorable risk-benefit profile.9 It should be tried initially at an adequate dose and duration before considering an... 

Pain management is also of critical importance in patients with spinal cord compression. While dexamethasone will provide some benefit, opioid analgesics also should be used and titrated rapidly to achieve adequate pain control. 

Endorphins are found primarily in the limbic system, hypothalamus, and brainstem. Enkephalins and dynorphin (in smaller quantities) are found primarily in the periaqueductal gray matter (PAG) of the midbrain, the limbic system, and the hypothalamus. These endogenous substances mimic the effects of morphine and other opiate drugs at many points in the analgesic system, including in the dorsal horns of the spinal cord. 

Figure 8.2 The endogenous analgesic system. The three major components of the endogenous analgesic system include the periaqueductal gray matter in the midbrain nucleus raphe magnus in the medulla and pain inhibitory complex in the dorsal horns of the spinal cord. This system causes presynaptic inhibition of pain fibers entering the spinal cord. The binding of enkephalin to opioid receptors on the pain fibers prevents release of the neurotransmitter, substance P. As a result, the pain signal is terminated in the spinal cord and does not ascend to higher centers in the CNS.

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