Pathways of Pain and Alternative Methods of Pain Relief
Have you ever wondered why when you stub your toe on the chair in the living room, it helps tremendously to yell out an expletive or two and vigorously rub the area? I may not be able to discuss the basis for such language in this paper, but we will explore the analgesic response to rubbing that toe, in addition to the mechanism of pain and alternative treatments such as acupuncture and transcutaneous electrical nerve stimulation.
In the two previous papers for this class I have chosen to focus upon the inherent power of the brain in relation to healing. Studies of the placebo effect and psychoneuroimmunology have ...view middle of the document...
We would not be able to change our behavior in any way when touching the burning hot dish in the oven, resulting in potentially serious burns. We could not recognize that perhaps we twisted an ankle when walking down the stairs, thus continued walking on that foot would exacerbate the injury to the point of not being able to walk at all. Indeed, pain is not pleasant, but in many cases it is an important way for our nervous system to learn from and react to the environment.
Mechanisms of Pain
What is the mechanism for pain sensation and response? Pain is a sensation characterized by unpleasant perceptual and emotional experiences that trigger various autonomic, psychological, and somatomotor responses. It is believed that this sensation consists basically of two types: 1) rapidly conducted action potentials carried by large- diameter myelinated axons, resulting in the sensation of sharp, well-localized pricking or cutting pain; 2) more slowly propagated action potentials carried by smaller, less heavily myelinated axons, resulting in the sensation of burning or aching pain (1). Variations in pain sensation result from the differences in integration of action potentials from pain receptors and the mechanisms by which pain receptors are stimulated. Usually, pain information originates in the periphery, for example, stubbing the toe. The change in tissue results in the release of substances from neurons adjacent to that tissue, possibly neuropeptides, serotonin, histamine, proteolytic enzymes, and prostaglandins, that activate pain fibers in the skin (2). It is believed that pain receptors are activated by the same stimuli that affect tactile and mechanoreceptors (1), since there may not be any specialized receptors or fibers that respond to noxious stimulation. Action potentials from tactile receptors probably help localize the source of pain and monitor changes in stimuli (1). This may explain why superficial pain is highly localized and perceived as sharp, since there is a high concentration of tactile receptors in the skin which are stimulated simultaneously as the pain receptors. Deep or visceral pain is often perceived as diffuse due to the absence of many mechanoreceptors in more deeper structures (1). Certain receptors have been identified which respond solely to noxious stimulation, called nociceptors. It has become possible to record the discharge frequency of these fibers and directly correlate the activity with the perceived intensity of pain (3).
The exact form of stimulus- response function is not known, but I we will look at some of the commonly accepted explanations. Concurrent activity in nociceptive and non-nociceptive fibers can strongly affect the perceived intensity of pain, demonstrating that convergence of afferent activity onto neurons in the spinal cord is key for pain mediation (3). Afferent fibers carry the nociceptive information from the periphery to the dorsal horn of the spinal cord. Several tracts in the...