Diverse firing properties and A beta-, A delta-, and C-afferent inputs of small local circuit neurons in spinal lamina I
| Autor: | Oleh Mytakhir, Liliana L. Luz, Nikolai V. Lukoyanov, Boris V. Safronov, Peter Szucs, Elisabete C Fernandes |
|---|---|
| Přispěvatelé: | Instituto de Investigação e Inovação em Saúde |
| Jazyk: | angličtina |
| Rok vydání: | 2016 |
| Předmět: |
0301 basic medicine
Action Potentials/physiology Spinal Cord Dorsal Horn Patch-Clamp Techniques Spinal Cord Dorsal Horn/cytology Nerve net Excitatory Postsynaptic Potentials/physiology Biophysics Action Potentials In Vitro Techniques Biology Nerve Fibers Myelinated Functional Laterality 03 medical and health sciences chemistry.chemical_compound 0302 clinical medicine Plateau potentials Interneurons Biocytin medicine Animals Patch clamp Elméleti orvostudományok Rats Wistar Nerve Fibers Unmyelinated/physiology Nerve Fibers Unmyelinated Nerve Fibers yelinated/physiology Excitatory Postsynaptic Potentials Orvostudományok Spinal cord Interneurons/physiology Electric Stimulation Rats Nerve Net/cytology 030104 developmental biology Anesthesiology and Pain Medicine medicine.anatomical_structure Nociception Animals Newborn nervous system Neurology chemistry Excitatory postsynaptic potential Neurology (clinical) Nerve Net Neuroscience 030217 neurology & neurosurgery |
| Zdroj: | Repositório Científico de Acesso Aberto de Portugal Repositório Científico de Acesso Aberto de Portugal (RCAAP) instacron:RCAAP |
| Popis: | Spinal lamina I is a key element of the pain processing system, which integrates primary afferent input and relays it to supraspinal areas. More than 90% of neurons in this layer are local circuit neurons, whose role in the signal processing is poorly understood. We performed whole-cell recordings in a spinal cord preparation with attached dorsal roots to examine morphological features and physiological properties of small local circuit neurons (n = 47) in lamina I. Cells successfully filled with biocytin (n = 17) had fusiform (n = 10), flattened (n = 4), and multipolar (n = 3) somatodendritic morphology; their axons branched extensively and terminated in laminae I-III. Intrinsic firing properties were diverse; in addition to standard tonic (n = 16), adapting (n = 7), and delayed (n = 6) patterns, small local circuit neurons also generated rhythmic discharges (n = 6) and plateau potentials (n = 10), the latter were suppressed by the L-type Ca(2+)-channel blocker nifedipine. The neurons received monosynaptic inputs from Aδ and C afferents and could generate bursts of spikes on the root stimulation. In addition, we identified lamina I neurons (n = 7) with direct inputs from the low-threshold Aβ afferents, which could be picked up by ventral dendrites protruding to lamina III. Stimulation of afferents also evoked a disynaptic inhibition of neurons. Thus, small local circuit neurons exhibit diverse firing properties, can generate rhythmic discharges and plateau potentials, and their dendrites extending into several laminae allow broad integration of Aβ-, Aδ-, and C-afferent inputs. These properties are required for processing diverse modalities of nociceptive inputs in lamina I and may underlie spinal sensitization to pain. This work is funded by FEDER funds through the Operational Competitiveness Programme—COMPETE and by national funds through FCT—Fundação para a Ciência e a Tecnologia under the project FCOMP-01-0124-FEDER-029623 (PTDC/NEU-SCC/0347/2012). |
| Databáze: | OpenAIRE |
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