Monosynaptic convergence of somatic and visceral C-fiber afferents on projection and local circuit neurons in lamina I: a substrate for referred pain
| Autor: | Liliana L. Luz, Peter Szucs, Elisabete C Fernandes, Eva Kokai, Miklós Sivadó, Boris V. Safronov |
|---|---|
| Přispěvatelé: | Instituto de Investigação e Inovação em Saúde |
| Rok vydání: | 2015 |
| Předmět: |
Visceral Afferents
Neural Conduction Integration Imaging 0302 clinical medicine Medicine Nerve Fibers Unmyelinated/physiology Neurons 0303 health sciences education.field_of_study Lysine/analogs & derivatives Dorsal horn Anatomy Referred pain Splanchnic Nerves/physiopathology medicine.anatomical_structure Neurology Pain Referred Convergence Synapses/physiology Lysine/metabolism Research Paper Spinal Cord Dorsal Horn Population Central nervous system Excitatory Postsynaptic Potentials/physiology Biophysics Stimulus (physiology) Inhibitory postsynaptic potential Splanchnic nerves Spinal Cord Dorsal Horn/pathology 03 medical and health sciences Animals Rats Wistar education Visceral Afferents/physiopathology 030304 developmental biology Nerve Fibers Unmyelinated business.industry Lysine Neural Conduction/physiology Excitatory Postsynaptic Potentials Splanchnic Nerves Action potential Spinal cord Electric Stimulation Rats Anesthesiology and Pain Medicine Synapses Neurology (clinical) business Neuroscience Neurons/physiology 030217 neurology & neurosurgery Pain Referred/pathology |
| Zdroj: | Pain Repositório Científico de Acesso Aberto de Portugal Repositório Científico de Acesso Aberto de Portugal (RCAAP) instacron:RCAAP |
| ISSN: | 1872-6623 |
| Popis: | Spinal lamina I is the first site in the central nervous system where somatic and visceral pathways monosynaptically converge onto projection and local circuit neurons. Referred pain is a phenomenon of feeling pain at a site other than the site of the painful stimulus origin. It arises from a pathological mixing of nociceptive processing pathways for visceral and somatic inputs. Despite numerous studies based on unit recordings from spinal and supraspinal neurons, the exact mechanism and site of this mixing within the central nervous system are not known. Here, we selectively recorded from lamina I neurons, using a visually guided patch-clamp technique, in thoracic spinal cord preparation with preserved intercostal (somatic) and splanchnic (visceral) nerves. We show that somatic and visceral C fibers converge monosynaptically onto a group of lamina I neurons, which includes both projection and local circuit neurons. Other groups of lamina I neurons received inputs from either somatic or visceral afferents. We have also identified a population of lamina I local circuit neurons showing overall inhibitory responses upon stimulation of both nerves. Thus, the present data allow us to draw two major conclusions. First, lamina I of the spinal cord is the first site in the central nervous system where somatic and visceral pathways directly converge onto individual projection and local circuit neurons. Second, the mechanism of somatovisceral convergence is complex and based on functional integration of monosynaptic and polysynaptic excitatory as well as inhibitory inputs in specific groups of neurons. This complex pattern of convergence provides a substrate for alterations in the balance between visceral and somatic inputs causing referred pain. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|