Biomaterial Database

Responses of spinal cord dorsal horn neurones to non-noxious and noxious cutaneous temperature changes in the spinal rat. 1979

D Menétrey, and A Chaouch, and J-M Besson

Unité de echerches de Neurophysiologie Pharmacologique de l'INSERM (U. 161), 2 rue d'Alésia, 75014 Paris France.

(1) Lumbar dorsal horn units characterized by their mechanical cutaneous sensitivities were tested for their responses to temperature changes of the skin in the decerebrate spinal rats. (a) Class 1 units (i.e. driven by non-noxious mechanical stimuli) were rarely thermally sensitive. (b) Nearly all class 2 units (i.e. driven by both non-noxious and noxious mechanical stimuli) and 4 of the 5 class 3 units (i.e. driven by noxious mechanical stimuli) were sensitive to temperature changes. (2) According to their thermal response threshold and their response range, these units were divided into 3 groups. (a) Warming units whose response threshold and maximum response were below 42.5 degrees C. Such units were rarely encountered. (b) Warming/noxious heat units whose response threshold was below 42.5 degrees C but with a maximum response above this temperature. They represented approximatively one-third of the radiant heat-sensitive units. (c) Noxious heat units whose response threshold was above 42.5 degrees C and maximum discharge several degrees above it. Approximately 50% of units activated by radiant heat belonged to this group. (3) Responses to radiant heat stimulation were frequently affected by a first noxious heat application. It consisted: --in a threshold decrease and/or an increase of their cellular discharge for a same temperature range. Only observed for warming/noxious heat units and noxious heat units, this sensitization phenomenon predminantly affected noxious heat units. --in a decrease of cellular discharge for a same temperature range. This desensitization phenomenon was observed for the 3 groups of units driven by radiant heat but mainly for warming units. (4) Supramaximal transcutaneous electrical stimulation revealed that nearly all the thermally sensitive units received A delta and/or C inputs. These units were largely distributed throughout the dorsal horn (laminae I, IV and V). Ten of the 12 lamina I units responded to noxious thermal stimuli. (5) These data indicate that an increase in skin temperature is coded at the level of the rat spinal cord dorsal horn by both an increase in discharge of low threshold temperature sensitive units and a progressive recruitment of high threshold units.

UI	MeSH Term	Description	Entries
D008297	Male		Males
D009433	Neural Inhibition	The function of opposing or restraining the excitation of neurons or their target excitable cells.	Inhibition, Neural
D009474	Neurons	The basic cellular units of nervous tissue. Each neuron consists of a body, an axon, and dendrites. Their purpose is to receive, conduct, and transmit impulses in the NERVOUS SYSTEM.	Nerve Cells,Cell, Nerve,Cells, Nerve,Nerve Cell,Neuron
D010812	Physical Stimulation	Act of eliciting a response from a person or organism through physical contact.	Stimulation, Physical,Physical Stimulations,Stimulations, Physical
D003080	Cold Temperature	An absence of warmth or heat or a temperature notably below an accustomed norm.	Cold,Cold Temperatures,Temperature, Cold,Temperatures, Cold
D003655	Decerebrate State	A condition characterized by abnormal posturing of the limbs that is associated with injury to the brainstem. This may occur as a clinical manifestation or induced experimentally in animals. The extensor reflexes are exaggerated leading to rigid extension of the limbs accompanied by hyperreflexia and opisthotonus. This condition is usually caused by lesions which occur in the region of the brainstem that lies between the red nuclei and the vestibular nuclei. In contrast, decorticate rigidity is characterized by flexion of the elbows and wrists with extension of the legs and feet. The causative lesion for this condition is located above the red nuclei and usually consists of diffuse cerebral damage. (From Adams et al., Principles of Neurology, 6th ed, p358)	Decerebrate Posturing,Decorticate Rigidity,Decorticate State,Rigidity, Decerebrate,Rigidity, Decorticate,Decerebrate Posturings,Decerebrate Rigidity,Decerebrate States,Decorticate Rigidities,Decorticate States,Posturing, Decerebrate,Posturings, Decerebrate,Rigidities, Decorticate,State, Decerebrate,States, Decerebrate
D004558	Electric Stimulation	Use of electric potential or currents to elicit biological responses.	Stimulation, Electric,Electrical Stimulation,Electric Stimulations,Electrical Stimulations,Stimulation, Electrical,Stimulations, Electric,Stimulations, Electrical
D006358	Hot Temperature	Presence of warmth or heat or a temperature notably higher than an accustomed norm.	Heat,Hot Temperatures,Temperature, Hot,Temperatures, Hot
D000818	Animals	Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA.	Animal,Metazoa,Animalia
D012684	Sensory Thresholds	The minimum amount of stimulus energy necessary to elicit a sensory response.	Sensory Threshold,Threshold, Sensory,Thresholds, Sensory