Pathological pain of peripheral origin

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This form of pathological pain occurs in chronic stimulation of pain receptors (nociceptors), damaged nociceptive fibers, spinal ganglia and dorsal root. These structures are often a source of intense and constant nociceptive stimulation. Nociceptors are activated in chronic inflammation (such as arthritis), the action of the decay products of tissues (eg, in tumors), and others. Chronically damageable (for example, when squeezed scars, overgrown bone and so forth.) And regenerating the sensory nerves, degenerative changed (under the action of various hazards, endocrinopathy) and demyelinated fibers are very sensitive to various humoral effects, even those for which they do not react under normal conditions (for example, to the action of epinephrine, K +, etc.). Sites such fibers are ectopic source of constant and significant nociceptive stimulation.

A special role is played by such a source neuroma - the formation of randomly overgrown nerve fibers, which occurs when they are disordered and difficulty increase. These endings are sensitive to a variety of mechanical, thermal, chemical and endogenous factors (eg, catecholamines). Therefore, the pain attacks with neuroma, as well as nerve damage can be triggered by different factors (for example, emotional stress, adrenaline action).

Nociceptive stimulation from the periphery of attack may cause pain if she overcomes the so-called "gating control" in the rear horns (Melzak, wall) consisting of a brake unit substantia gelatinosa neurons. These neurons control the flow entering the posterior horns and the ascending nociceptive stimulation. This effect can occur when intense afferent stimulation or by brake failure "gate-control."