Dorsal horn neuron response patterns to graded heat stimuli in the rat

• Published in: Brain research Vol. 1045; no. 1; pp. 72 - 79
• Main Authors: Borzan, Jasenka, LaGraize, Stacey C., Hawkins, Doyle L., Peng, Yuan B.
• Format: Journal Article
• Language: English
• Published: London Elsevier B.V 31.05.2005; Amsterdam Elsevier; New York, NY
• Subjects: Action Potentials - physiology; Afferent Pathways - physiology; Animals; Biological and medical sciences; Dorsal horn neuron; Fundamental and applied biological sciences. Psychology; Ganglia, Spinal - physiology; Hot Temperature; Male; Neural Inhibition - physiology; Physical Stimulation; Posterior Horn Cells - physiology; Primary afferent; Rats; Rats, Sprague-Dawley; Sensory Receptor Cells - physiology; Skin - innervation; Somesthesis and somesthetic pathways (proprioception, exteroception, nociception); interoception; electrolocation. Sensory receptors; Spinal cord; Synapse; Synaptic Transmission - physiology; Thermosensing - physiology; Vertebrates: nervous system and sense organs; Sensory systems; Dorsal horn neuron; Spinal cord; Synapse; Primary afferent; Nociception; Temperature; Rat; Rodentia; Central nervous system; Thermal stimulus; Environmental factor; Posterior spinal horn; Vertebrata; Heat; Mammalia; Neuron; Animal
• ISSN: 0006-8993; 1872-6240
• DOI: 10.1016/j.brainres.2005.03.030

Sensory input from various receptors in the periphery first becomes integrated in the spinal cord dorsal horn. The response of the spinal cord dorsal horn neurons to mechanical stimuli are classified as low threshold, high threshold, and wide dynamic range neurons. However, the response pattern of deep dorsal horn cells to heat has not been well described. In this study, the response of the spinal cord dorsal horn neurons to graded heat stimuli were characterized in 147 neurons in rats by extracellular single cell recording. After a differentiable cell was identified, the Peltier heat stimulator was applied to the receptive field and the base temperature was set at 30 °C. The heat stimulus was delivered for 10 s from 37–51 °C in 2 °C increments, with an inter-stimulus interval of 30 s. Out of the 147 neurons, five statistically distinguishable response patterns were identified by latent class cluster analysis. It is concluded that variation of temperature may account for the observed results and indicate functionally different subsets of heat-responsive cells in the deep dorsal horn.