Related Experiment Video
Updated: Aug 10, 2026
07:49
Measuring Changes in Tactile Sensitivity in the Hind Paw of Mice Using an Electronic von Frey Apparatus
Published on: December 19, 2013
Central origin of secondary mechanical hyperalgesia
Monika Klede1, Hermann O Handwerker, Martin Schmelz
1Department of Physiology and Experimental Pathophysiology, University of Erlangen/Nürnberg, 91054 Erlangen, Germany.
Journal of Neurophysiology
|July 5, 2003
Summary
Peripheral mechanisms
Area of Science:
- Neuroscience
- Pain Research
- Dermatology
Background:
- The role of peripheral mechanisms in secondary mechanical hyperalgesia is not fully understood.
- Previous research has not definitively clarified the contribution of peripheral factors to pain sensitization.
Purpose of the Study:
- To investigate the effects of local anesthetics on electrically induced flare reactions and mechanical hyperalgesia in human skin.
- To differentiate between central and peripheral contributions to pain development.
Main Methods:
- A narrow anesthetic strip was created using intradermal microdialysis of lidocaine in human forearm skin.
- Electrical stimulation was applied near the anesthetic strip, and flare reactions (vasodilation) and hyperalgesia were assessed.
- Laser Doppler scanning, infrared thermography, and subjective pain measurements were utilized.
Main Results:
- Lidocaine significantly reduced flare area and intensity, indicating peripheral mediation of vasodilation.
- Mechanical hyperalgesia (allodynia and punctate hyperalgesia) developed equally on both sides of the anesthetic strip.
- Hyperalgesia resolved quickly after stimulation cessation, suggesting central sensitization.
Conclusions:
- The development of mechanical hyperalgesia in human skin is primarily centrally mediated.
- Axon reflex vasodilation, a component of the flare reaction, originates from peripheral mechanisms.
- This study distinguishes between central pain processing and peripheral inflammatory responses.
Related Concept Videos
01:33Somatosensation
The somatosensory system relays sensory information from the skin, mucous membranes, limbs, and joints. Somatosensation is more familiarly known as the sense of touch. A typical somatosensory pathway includes three types of long neurons: primary, secondary, and tertiary. Primary neurons have cell bodies located near the spinal cord in groups of neurons called dorsal root ganglia. The sensory neurons of ganglia innervate designated areas of skin called dermatomes.
01:43Thermosensation
Peripheral thermosensation is the perception of external temperature. A change in temperature (on the surface of the skin and other tissues) is detected by a family of temperature-sensitive ion channels called Transient Receptor Potential, or TRP, receptors. These receptors are located on free nerve endings. Those detecting cold temperatures are closer to the surface of the skin than the nerve endings detecting warmth. These thermoTRP channels, while temperature selective, have relatively...
01:44Nociception
Nociception—the ability to feel pain—is essential for an organism’s survival and overall well-being. Noxious stimuli such as piercing pain from a sharp object, heat from an open flame, or contact with corrosive chemicals are first detected by sensory receptors, called nociceptors, located on nerve endings. Nociceptors express ion channels that convert noxious stimuli into electrical signals. When these signals reach the brain via sensory neurons, they are perceived as pain. Thus, pain helps the...
01:28Major Somatic Sensory Pathways
Sensory impulses related to touch, pressure, vibration, and proprioception from various body parts, such as the limbs, trunk, neck, and posterior head, travel to the cerebral cortex through the posterior column-medial lemniscus pathway. The pathway’s name derives from the two white-matter tracts that convey the impulses: the spinal cord's posterior column and the brainstem's medial lemniscus. First-order sensory neurons extend their axons into the spinal cord, forming the posterior columns...
01:20Pain
Pain serves as a critical warning signal that alerts the body to potential or actual harm. When mechanical pressure on the skin is intense, such as from a sharp pinch, the sensation transitions from touch to pain. Similarly, extreme temperatures, like a hot pot handle, convert the sensation of heat into pain. Pain can also result from overstimulation of other senses, such as blinding light, loud noise, or the intense heat from habañero peppers. This ability to sense pain is essential for...
01:25Secondary Spinal Cord Injury llI: Pathophysiology
Early Ischemia and Ionic ImbalanceWithin minutes of spinal cord injury, a secondary cascade begins, progressing over hours to weeks. Vascular damage reduces blood flow, causing ischemia and mitochondrial dysfunction. ATP depletion leads to ion pump failure, membrane depolarization, sodium influx, potassium efflux, and water accumulation, resulting in cellular swelling. Increased intracellular calcium further disrupts mitochondria and accelerates cellular injury.Excitotoxicity and Neuronal...