High-threshold primary afferent supply of spinal lamina X neurons. Issue 9 (September 2019)

• Record Type: Journal Article
• Authors: Krotov, Volodymyr; Tokhtamysh, Anastasia; Safronov, Boris V.; Belan, Pavel; Voitenko, Nana
• Is Part Of: Pain. Volume 160:Issue 9(2019)
• Publication Date: 2019-09
• Subjects: Spinal cord -- Lamina X neurons -- Primary afferent inputs -- High-threshold Aδ- and C-fibers -- Monosynaptic contacts -- Polysynaptic inhibition; Pain -- Periodicals; Douleur -- Périodiques; Anesthésie -- Périodiques; Pain; Electronic journals; Periodicals; Electronic journals; 616.0472
• DOI: 10.1097/j.pain.0000000000001586
• Languages: English
• ISSNs: 0304-3959

Abstract

Abstract : Abstract: The spinal gray matter region around the central canal, lamina X, is critically involved in somatosensory processing and visceral nociception. Although several classes of primary afferent fibers terminate or decussate in this area, little is known about organization and functional significance of the afferent supply of lamina X neurons. Using the hemisected ex vivo spinal cord preparation, we show that virtually all lamina X neurons receive primary afferent inputs, which are predominantly mediated by the high-threshold Aδ- fibers and C-fibers. In two-thirds of the neurons tested, the inputs were monosynaptic, implying a direct targeting of the population of lamina X neurons by the primary nociceptors. Beside the excitatory inputs, 48% of the neurons also received polysynaptic inhibitory inputs. A complex pattern of interactions between the excitatory and inhibitory components determined the output properties of the neurons, one-third of which fired spikes in response to the nociceptive dorsal root stimulation. In this respect, the spinal gray matter region around the central canal is similar to the superficial dorsal horn, the major spinal nociceptive processing area. We conclude that lamina X neurons integrate direct and indirect inputs from several types of thin primary afferent fibers and play an important role in nociception. Abstract : Supplemental Digital Content is Available in the Text.Spinal lamina X neurons integrate direct and indirect inputs from several types of thin primary afferent fibers, thus playing an important role in nociception.