Perception of pain

Analgesics interfere with the generation and/or transmission of impulses following noxious stimulation ( nociception) in the nervous system. This can occur at peripheral and/or central levels of the neuraxis. The therapeutic aim is to diminish the perception of pain. 

Opioids bound to MOR on postsynaptic terminals promote the efflnx of potassinm (K ) via K+ channels. The net effect of active MOR receptor resnlts in hyperpolarization of the post-synapse causing inhibition of neuronal firing. Stndies have shown MOR effects at the pre- and post-synapse synergistically decreases the perception of pain (Glanm et al. 1994 Kohno et al. 1999 Williams et al. 2001 Yoshimnra and North 1983). 

A second theory of phantom pain suggests that second-order neurons in the dorsal horn of the spinal cord become hyperactive. Spontaneous firing of these neurons causes transmission of nerve impulses to the brain and the perception of pain. 

Arachidonic acid (C20 4 n-6) is the precursor for the synthesis of prostaglandin molecules (Section 4.4.4), which have a wide range of biochemical effects on for example, the perception of pain, inflammation, blood clotting and smooth muscle contraction. Docosahexaenoic acid (DHA, C22 6) and eicosapentaenoic acid (EPA, C20 5) are both n-3 long-chain polyunsaturated fatty acids (PUFA) which have been shown to have significantly beneficial effects on intellectual development and inflammatory conditions such as asthma and cardiovascular disease. 

Plays a key role in the perception of pain induced by thermal, chemical, physical, and mechanical stimuli. 9- ... 

Selective serotonin reuptake inhibitors have not been well studied in patients with chronic pain, nor has the role of serotonin been elucidated. However some clinical experience suggests that the perception of pain is diminished with selective serotonin reuptake inhibitors. 

Opioids have profound effects upon the cerebrocor-tical regions that control the somatosensory and discriminative aspects of pain. Thus, the opioids suppress the perception of pain by eliminating or altering the emotional aspects of pain and inducing euphoria and sleep... 

Glutamate activates the N-methyl-D-aspartate (NMDA) receptor. Glutamate is involved in perception of pain, sensory input, and memory. PCP and dextromethorphan block this receptor. 

Analgesia Morphine produces analgesia by elevation of pain threshold, thereby reducing the perception of pain. It also altered psychic reaction to pain which maybe associated with feeling of well being e.g. euphoria. It also produces lethargy and sleep, morphine relieves all types of pain, but dull constant pain is relieved more ef-... 

Brain serotonergic neurons are involved in numerous diffuse functions such as mood, sleep, appetite, and temperature regulation, as well as the perception of pain, the regulation of blood pressure, and vomiting (see Chapter 21). Serotonin also appears to be involved in clinical conditions such as depression, anxiety, and migraine. Serotonergic neurons are also found in the enteric nervous system of the gastrointestinal tract and around blood vessels. In rodents (but not in humans), serotonin is found in mast cells. 

Basbaum AI, Jessel T The perception of pain. In Kandel ER et al (editors) Principles of Neural Science, 4th ed. McGraw-Hill, 2000. 

Medico-technical instruments such as infusion pumps can be used in PCA (patient-controlled analgesia, Fig. 1) to provide patient-orientated and therapy as required, e.g. with morphine injection solutions. Depending on the patients perception of pain, they may add small doses of analgesics to the basic infusion by means of an electrically controlled infusion pump. The physician specifies the basic dose, which is infused independent of patient demands, the boluses that can be demanded, an hourly maximum dose and a refractory time that cannot be reduced between two doses. The infusion may be given intravenously, subcutaneously, epidurally or intraspinally. 

Pain Relievers Inhibit the Transmission or Perception of Pain... 

PAIN RELIEVERS INHIBIT THE TRANSMISSION OR PERCEPTION OF PAIN... 

Analgesia means lack of pain, and analgesics are substances that obtund the perception of pain without causing loss of consciousness. However, analgesics should not be given until the cause of pain has been determined. If a proper diagnosis is made, the use of an analgesic may not be... 

By modifying the central perception of pain of peripheral origin and mitigating psychogenic pain by depressing reflex activity with such drugs as alcohol, the barbiturates, etc. 

---