Cat's medullary reticulospinal and subnucleus reticularis dorsalis noxious neurons form a coupled neural circuit through collaterals of descending axons
| Autor: | Antonio Canedo, Patricia Velo, Roberto Leiras, Francisco J. Martín-Cora, Tania Liste |
|---|---|
| Rok vydání: | 2015 |
| Předmět: |
0301 basic medicine
Male Nociception Hot Temperature Medullary cavity Physiology Action Potentials Biology Neural Circuits 03 medical and health sciences 0302 clinical medicine Neural Pathways Noxious stimulus medicine Animals Neurons Medulla Oblongata CATS General Neuroscience Cervical Cord Axons 030104 developmental biology medicine.anatomical_structure Reticular connective tissue Medulla oblongata Excitatory postsynaptic potential Cats Soma Neuroscience 030217 neurology & neurosurgery |
| Zdroj: | Journal of neurophysiology. 115(1) |
| ISSN: | 1522-1598 |
| Popis: | Animals and human beings sense and react to real/potential dangerous stimuli. However, the supraspinal mechanisms relating noxious sensing and nocifensive behavior are mostly unknown. The collateralization and spatial organization of interrelated neurons are important determinants of coordinated network function. Here we electrophysiologically studied medial medullary reticulospinal neurons (mMRF-RSNs) antidromically identified from the cervical cord of anesthetized cats and found that 1) more than 40% (79/183) of the sampled mMRF-RSNs emitted bifurcating axons running within the dorsolateral (DLF) and ventromedial (VMF) ipsilateral fascicles; 2) more than 50% (78/151) of the tested mMRF-RSNs with axons running in the VMF collateralized to the subnucleus reticularis dorsalis (SRD) that also sent ipsilateral descending fibers bifurcating within the DLF and the VMF. This percentage of mMRF collateralization to the SRD increased to more than 81% (53/65) when considering the subpopulation of mMRF-RSNs responsive to noxiously heating the skin; 3) reciprocal monosynaptic excitatory relationships were electrophysiologically demonstrated between noxious sensitive mMRF-RSNs and SRD cells; and 4) injection of the anterograde tracer Phaseolus vulgaris leucoagglutinin evidenced mMRF to SRD and SRD to mMRF projections contacting the soma and proximal dendrites. The data demonstrated a SRD-mMRF network interconnected mainly through collaterals of descending axons running within the VMF, with the subset of noxious sensitive cells forming a reverberating circuit probably amplifying mutual outputs simultaneously regulating motor activity and spinal noxious afferent input. The results provide evidence that noxious stimulation positively engages a reticular SRD-mMRF-SRD network involved in pain-sensory-to-motor transformation and modulation. |
| Databáze: | OpenAIRE |
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