Biomaterial Database

Effects of tooth pulp deafferentation on nociceptive and nonnociceptive neurons of the feline trigeminal subnucleus caudalis (medullary dorsal horn). 1989

J W Hu, and B J Sessle

Faculty of Dentistry, University of Toronto, Ontario, Canada.

1. Effects of deafferentation of the tooth pulps of the posterior mandibular teeth were studied in single neurons recorded in the ipsilateral subnucleus caudalis of the trigeminal (V) spinal tract nucleus of adult cats and kittens. The functional properties of neurons in each anesthetized animal were determined electro-physiologically in a series of microelectrode penetrations of the subnucleus. 2. The more than 800 neurons investigated could be subdivided on the basis of their cutaneous mechanoreceptive field properties into low-threshold mechanoreceptive (LTM) neurons, wide dynamic range (WDR) neurons, or nociceptive-specific (NS) neurons. Comparisons of neuronal properties were made between control (intact) cats and 7-15 day deafferented cats studied in a blind design, as well as groups of longer term deafferented cats, and kittens undergoing a "natural" deafferentation as a result of exfoliation of primary teeth. 3. There was no apparent change in the somatotopic pattern of organization of the subnucleus in the kittens and pulp-deafferented cats and no statistically significant differences were noted between kittens and control cats in any property except for alterations in the incidence of spontaneously active neurons. 4. Limited but statistically significant alterations were noted in some of the neuronal properties in the deafferented cats. These changes were especially apparent in the LTM neurons. The incidence of spontaneous activity was significantly decreased in the neurons of most long-term deafferented groups of cats. In the 7-15 day deafferented group, significantly more LTM neurons had a mechanoreceptive field involving all three divisions of the V nerve, and there was a significant increase in the incidence of LTM neurons activated by electrical stimulation of intraoral sites. Mechanosensitive neurons responsive only to tap stimuli were found only in the deafferented groups of cats. 5. These alterations in caudalis contrast with previous reports claiming marked hyperexcitability of caudal V brain stem neurons as a consequence of deafferentation and implicating such effects in the development of pain. However, some of the changes are in general not inconsistent with deafferentation-induced changes reported in spinal somatosensory neurons and with the pulp deafferentation-induced changes that we have recently documented in LTM neurons of subnucleus oralis of the V spinal tract nucleus of adult cats.(ABSTRACT TRUNCATED AT 400 WORDS)

UI	MeSH Term	Description	Entries
D008839	Microelectrodes	Electrodes with an extremely small tip, used in a voltage clamp or other apparatus to stimulate or record bioelectric potentials of single cells intracellularly or extracellularly. (Dorland, 28th ed)	Electrodes, Miniaturized,Electrode, Miniaturized,Microelectrode,Miniaturized Electrode,Miniaturized Electrodes
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
D009619	Nociceptors	Peripheral AFFERENT NEURONS which are sensitive to injuries or pain, usually caused by extreme thermal exposures, mechanical forces, or other noxious stimuli. Their cell bodies reside in the DORSAL ROOT GANGLIA. Their peripheral terminals (NERVE ENDINGS) innervate target tissues and transduce noxious stimuli via axons to the CENTRAL NERVOUS SYSTEM.	Pain Receptors,Receptors, Pain,Nociceptive Neurons,Neuron, Nociceptive,Neurons, Nociceptive,Nociceptive Neuron,Nociceptor,Pain Receptor
D002415	Cats	The domestic cat, Felis catus, of the carnivore family FELIDAE, comprising over 30 different breeds. The domestic cat is descended primarily from the wild cat of Africa and extreme southwestern Asia. Though probably present in towns in Palestine as long ago as 7000 years, actual domestication occurred in Egypt about 4000 years ago. (From Walker's Mammals of the World, 6th ed, p801)	Felis catus,Felis domesticus,Domestic Cats,Felis domestica,Felis sylvestris catus,Cat,Cat, Domestic,Cats, Domestic,Domestic Cat
D003714	Denervation	The resection or removal of the nerve to an organ or part.	Laser Neurectomy,Neurectomy,Peripheral Neurectomy,Radiofrequency Neurotomy,Denervations,Laser Neurectomies,Neurectomies,Neurectomies, Laser,Neurectomies, Peripheral,Neurectomy, Laser,Neurectomy, Peripheral,Neurotomies, Radiofrequency,Neurotomy, Radiofrequency,Peripheral Neurectomies,Radiofrequency Neurotomies
D005071	Evoked Potentials	Electrical responses recorded from nerve, muscle, SENSORY RECEPTOR, or area of the CENTRAL NERVOUS SYSTEM following stimulation. They range from less than a microvolt to several microvolts. The evoked potential can be auditory (EVOKED POTENTIALS, AUDITORY), somatosensory (EVOKED POTENTIALS, SOMATOSENSORY), visual (EVOKED POTENTIALS, VISUAL), or motor (EVOKED POTENTIALS, MOTOR), or other modalities that have been reported.	Event Related Potential,Event-Related Potentials,Evoked Potential,N100 Evoked Potential,P50 Evoked Potential,N1 Wave,N100 Evoked Potentials,N2 Wave,N200 Evoked Potentials,N3 Wave,N300 Evoked Potentials,N4 Wave,N400 Evoked Potentials,P2 Wave,P200 Evoked Potentials,P50 Evoked Potentials,P50 Wave,P600 Evoked Potentials,Potentials, Event-Related,Event Related Potentials,Event-Related Potential,Evoked Potential, N100,Evoked Potential, N200,Evoked Potential, N300,Evoked Potential, N400,Evoked Potential, P200,Evoked Potential, P50,Evoked Potential, P600,Evoked Potentials, N100,Evoked Potentials, N200,Evoked Potentials, N300,Evoked Potentials, N400,Evoked Potentials, P200,Evoked Potentials, P50,Evoked Potentials, P600,N1 Waves,N2 Waves,N200 Evoked Potential,N3 Waves,N300 Evoked Potential,N4 Waves,N400 Evoked Potential,P2 Waves,P200 Evoked Potential,P50 Waves,P600 Evoked Potential,Potential, Event Related,Potential, Event-Related,Potential, Evoked,Potentials, Event Related,Potentials, Evoked,Potentials, N400 Evoked,Related Potential, Event,Related Potentials, Event,Wave, N1,Wave, N2,Wave, N3,Wave, N4,Wave, P2,Wave, P50,Waves, N1,Waves, N2,Waves, N3,Waves, N4,Waves, P2,Waves, P50
D000344	Afferent Pathways	Nerve structures through which impulses are conducted from a peripheral part toward a nerve center.	Afferent Pathway,Pathway, Afferent,Pathways, Afferent
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
D014070	Tooth	One of a set of bone-like structures in the mouth used for biting and chewing.	Teeth
D014275	Trigeminal Caudal Nucleus	The caudal portion of the nucleus of the spinal trigeminal tract (TRIGEMINAL NUCLEUS, SPINAL), a nucleus involved with pain and temperature sensation.	Caudal Nucleus, Trigeminal,Nucleus, Trigeminal Caudal