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Spinal CordAnatomical and Physiological Features
Published in Peter Kam, Ian Power, Michael J. Cousins, Philip J. Siddal, Principles of Physiology for the Anaesthetist, 2020
Peter Kam, Ian Power, Michael J. Cousins, Philip J. Siddal
The spinal cord is divided into two regions, the white matter and the grey matter. The centre of the cord contains the ‘H’-shaped grey matter, surrounded by the white matter (Figure 7.1). The white matter around the grey matter contains the ascending and descending tracts (pathways). The grey matter contains the unmyelinated nerve fibres and the cell bodies of the interneurons and motor neurons. It can be subdivided into the dorsal horn, which is associated with sensory perception, and the ventral horn, which is associated with motor functions such reflex movements.
The nervous system
Published in Laurie K. McCorry, Martin M. Zdanowicz, Cynthia Y. Gonnella, Essentials of Human Physiology and Pathophysiology for Pharmacy and Allied Health, 2019
Laurie K. McCorry, Martin M. Zdanowicz, Cynthia Y. Gonnella
A cross-sectional view of the spinal cord reveals that the gray matter has an H-shape (also referred to a butterfly shape) (see Figure 13.4) and is divided into three regions called horns. Dorsal horn (posterior, toward the back)Ventral horn (anterior, toward the front)Lateral horn (toward the side)
Pain Medicine
Published in Elizabeth Combeer, The Final FRCA Short Answer Questions, 2019
Repeated peripheral nerve stimulation or nerve damage causes increased sodium channel expression, resulting in reduced threshold for, or spontaneous, firing of peripheral nerves. This results in increased glutamate release from these first-order neurones at the dorsal horn. Glutamate receptor density of postsynaptic membranes on second-order neurones increases. Transmission occurs in previously inactive second-order neurones, neurones that do not normally transmit pain information, and transmission may persist beyond duration of initial input, ‘central sensitisation.’
PU.1 interaction with p50 promotes microglial-mediated inflammation in secondary spinal cord injury in SCI rats
Published in International Journal of Neuroscience, 2023
Mingchen Yu, Yiqing Ou, Hongmei Wang, Weidong Gu
The number of PU.1-positive cells on the spinal cord sections taken at 2 mm from the injury epicenter was counted in 500 × 500 μm frames. For each animal, the transverse sections of the dorsal horn, lateral funiculus, and ventral horn were selected. The cell counts were then used to determine the total number of PU.1-positive cells per square millimeter. The percentage of cells that stained positive for PU.1 or p-p50 was also quantified. The cells double stained with PU.1 and NeuN, GFAP, or Iba-1, as well as cells double stained with PU.1 and OX42 or p-p50, were also quantified. To identify the proportion of PU.1-expressing cells with positive expression of specific phenotypic markers, a minimum of 200 cells positive for the specific phenotypic markers in the white and gray matter of the sections were included. We then recorded the number of cells double-labeled with PU.1 and cell-specific markers. Two or three adjacent sections taken at 2 mm from the injury epicenter were used for quantitative analysis.
Treating osteoarthritis pain: mechanisms of action of acetaminophen, nonsteroidal anti-inflammatory drugs, opioids, and nerve growth factor antibodies
Published in Postgraduate Medicine, 2021
Yvonne D’Arcy, Patrick Mantyh, Tony Yaksh, Sean Donevan, Jerry Hall, Mojgan Sadrarhami, Lars Viktrup
The dorsal horn is a key structure in the processing and modulation of pain signals. Second-order neurons in the dorsal horn respond to high-intensity nociceptive afferent input (marginal neurons) or to both nociceptive and non-nociceptive afferent input (wide dynamic range neurons) [19]. In both cases, the encoding of stimulus intensity by these projection neurons largely depends on their discharge rate, with higher discharge rates associated with a more intense (i.e. painful) signal. However, the output function of the dorsal horn is subject to modulation via bulbospinal projections arising from brainstem structures (e.g. rostral ventromedial medulla [RVM] and locus coeruleus [LC]) that can variously serve to augment (i.e. descending facilitation) or down regulate (i.e. descending inhibition) dorsal horn excitability to modulate the firing rate of these second-order neurons [20,24].
Calcium-independent phospholipase A2 inhibitor produces an analgesic effect in a rat model of neuropathic pain by reducing central sensitization in the dorsal horn
Published in Neurological Research, 2021
Young Seob Gwak, Guanxing Chen, Salahadin Abdi, Hee Kee Kim
Central sensitization of the spinal cord’s dorsal horn is a well-known underlying mechanism of neuropathic pain. In central sensitization, peripheral sensory stimuli produce exaggerated responses in dorsal horn neurons and then contribute to persistent pain behaviors, including spontaneous and evoked pain via imbalances between excitatory and inhibitory circuits, alteration of ion channels/receptors, inflammatory process, and re-construction of synaptic plasticity [26]. Central sensitization in the dorsal horn neurons is predominantly regulated by dysfunctional intracellular calcium ion homeostasis. In the present study, we report that BEL, a selective iPLA2 inhibitor, inhibits hyperexcitability of WDR neurons, suggesting that a calcium-independent mechanism is also involved in central sensitization. The calcium-independent enzyme iPLA2regulates adenosine triphosphate (ATP), caspase cleavage, calmodulin, and ankyrin-mediated oligomerization [27]. In the nervous system, it mediates multiple synaptic signaling mechanisms, including those involved in cortical development, synaptic remodeling, glutamate-receptor, long–term potentiation, and neuronal plasticity [28-30]. Therefore, our data suggest that iPLA2 may be responsible for the calcium-independent maintenance of the hyperexcitability of WDR neurons in the dorsal horn.