Biomaterial Database

Morphology of functional long-ranging primary afferent projections in the cat spinal cord. 1995

H R Koerber, and K Mirnics

Department of Neurobiology, University of Pittsburgh, School of Medicine, Pennsylvania 15261, USA.

1. A beta-cutaneous primary afferent fibers were impaled in the dorsal columns of alpha-chloralose-anesthetized cats. Penetrations were made with the use of electrodes filled with 2 or 5% N-(2-aminoethyl) biotinamide hydrochloride (Neurobiotin, NB) in 0.1 or 1 M KCl. After determining its adequate stimulus, each fiber was activated by current pulses (18 Hz) injected via the microelectrode. The resulting cord dorsum potential (CDP) was recorded at four locations. NB was then injected into the fiber with the use of positive current pulses (11-22 nA) and a 75% duty cycle. 2. After allowing 2-8 h for diffusion, animals were perfused with saline (37 degrees C) followed by 4% paraformaldehyde (4 degrees C). Frozen 50-microns sections were cut in either the transverse or sagittal plane, processed on slides with the use of standard avidin-biotin protocols, and visualized by the nickel-enhanced diaminobenzidine (DAB) reaction. 3. A total of 15 A beta-cutaneous afferents innervating both rapidly (RA) and slowly adapting (SA) receptors were adequately stained and their central projections recovered. For selected fibers the rostrocaudal and laminar bouton distributions were determined and compared with the distribution of monosynaptic CDP amplitudes recorded at the four surface locations. 4. The rostrocaudal extent of a single A beta-afferent fiber bouton distribution visualized with NB ranged from 8 to 17.5 mm (14.4 +/- 2.4 mm, mean +/- SD), or two to three times greater than that previously shown with the use of horseradish peroxidase (HRP). 5. The strong correlation between the rostrocaudal distribution of boutons and monosynaptic CDP amplitudes, and the improved agreement between modeled and observed CDP amplitudes over that seen previously with the use of HRP (mean percent error, HRP = 23 +/- 2.9%; NB = 9 +/- 2.3%), suggest that boutons along the entire length of the visualized distribution contribute to the recorded potentials. 6. Taken together, these findings suggest that inputs from a given point on the skin can directly influence sensory information processing over a much greater rostrocaudal extent than predicted by dorsal horn somatotopic maps. These findings are discussed in terms of their implications for spinal cord plasticity.

UI	MeSH Term	Description	Entries
D008297	Male		Males
D009412	Nerve Fibers	Slender processes of NEURONS, including the AXONS and their glial envelopes (MYELIN SHEATH). Nerve fibers conduct nerve impulses to and from the CENTRAL NERVOUS SYSTEM.	Cerebellar Mossy Fibers,Mossy Fibers, Cerebellar,Cerebellar Mossy Fiber,Mossy Fiber, Cerebellar,Nerve Fiber
D009431	Neural Conduction	The propagation of the NERVE IMPULSE along the nerve away from the site of an excitation stimulus.	Nerve Conduction,Conduction, Nerve,Conduction, Neural,Conductions, Nerve,Conductions, Neural,Nerve Conductions,Neural Conductions
D009473	Neuronal Plasticity	The capacity of the NERVOUS SYSTEM to change its reactivity as the result of successive activations.	Brain Plasticity,Plasticity, Neuronal,Axon Pruning,Axonal Pruning,Dendrite Arborization,Dendrite Pruning,Dendritic Arborization,Dendritic Pruning,Dendritic Remodeling,Neural Plasticity,Neurite Pruning,Neuronal Arborization,Neuronal Network Remodeling,Neuronal Pruning,Neuronal Remodeling,Neuroplasticity,Synaptic Plasticity,Synaptic Pruning,Arborization, Dendrite,Arborization, Dendritic,Arborization, Neuronal,Arborizations, Dendrite,Arborizations, Dendritic,Arborizations, Neuronal,Axon Prunings,Axonal Prunings,Brain Plasticities,Dendrite Arborizations,Dendrite Prunings,Dendritic Arborizations,Dendritic Prunings,Dendritic Remodelings,Network Remodeling, Neuronal,Network Remodelings, Neuronal,Neural Plasticities,Neurite Prunings,Neuronal Arborizations,Neuronal Network Remodelings,Neuronal Plasticities,Neuronal Prunings,Neuronal Remodelings,Neuroplasticities,Plasticities, Brain,Plasticities, Neural,Plasticities, Neuronal,Plasticities, Synaptic,Plasticity, Brain,Plasticity, Neural,Plasticity, Synaptic,Pruning, Axon,Pruning, Axonal,Pruning, Dendrite,Pruning, Dendritic,Pruning, Neurite,Pruning, Neuronal,Pruning, Synaptic,Prunings, Axon,Prunings, Axonal,Prunings, Dendrite,Prunings, Dendritic,Prunings, Neurite,Prunings, Neuronal,Prunings, Synaptic,Remodeling, Dendritic,Remodeling, Neuronal,Remodeling, Neuronal Network,Remodelings, Dendritic,Remodelings, Neuronal,Remodelings, Neuronal Network,Synaptic Plasticities,Synaptic Prunings
D009475	Neurons, Afferent	Neurons which conduct NERVE IMPULSES to the CENTRAL NERVOUS SYSTEM.	Afferent Neurons,Afferent Neuron,Neuron, Afferent
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
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
D005260	Female		Females
D006651	Histocytochemistry	Study of intracellular distribution of chemicals, reaction sites, enzymes, etc., by means of staining reactions, radioactive isotope uptake, selective metal distribution in electron microscopy, or other methods.	Cytochemistry
D000344	Afferent Pathways	Nerve structures through which impulses are conducted from a peripheral part toward a nerve center.	Afferent Pathway,Pathway, Afferent,Pathways, Afferent