Abstract
The effect of neonatal capsaicin treatment, producing selective elimination of almost all unmyelinated C-fiber sensory axons, was studied on lesion-induced transganglionic labelling of the substantia gelatinosa of the spinal cord by choleragenoid. In both control and capsaicin-pretreated rats, the injection of choleragenoid-horseradish peroxidase conjugate into the intact sciatic nerves resulted in intense labelling only of the deeper layers of the spinal dorsal horn. In the control but not the capsaicin-pretreated rats, the injection of the tracer into sciatic nerves transected 2 weeks previously produced an intense homogeneous labelling of the substantia gelatinosa. It is concluded that the uptake and axonal transport of choleragenoid by capsaicin-sensitive C-fiber afferents may be accounted for by the lesion-induced transganglionic labelling of the substantia gelatinosa, rather than by A-fiber sprouting.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Afferent Pathways / injuries*
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Afferent Pathways / physiopathology
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Animals
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Axonal Transport / drug effects
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Axonal Transport / physiology*
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Capsaicin / pharmacology
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Cell Size / physiology
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Cholera Toxin / pharmacokinetics*
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Denervation
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Disease Models, Animal
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Ganglia, Spinal / cytology
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Ganglia, Spinal / drug effects
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Ganglia, Spinal / metabolism
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Growth Cones / drug effects
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Growth Cones / metabolism
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Growth Cones / ultrastructure
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Horseradish Peroxidase / pharmacokinetics
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Male
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Nerve Degeneration / chemically induced
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Nerve Degeneration / pathology
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Nerve Degeneration / physiopathology
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Nerve Fibers, Myelinated / drug effects
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Nerve Fibers, Myelinated / metabolism
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Nerve Fibers, Unmyelinated / drug effects
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Nerve Fibers, Unmyelinated / metabolism*
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Neuronal Plasticity / physiology
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Peripheral Nerve Injuries*
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Peripheral Nerves / physiopathology
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Presynaptic Terminals / drug effects
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Presynaptic Terminals / metabolism
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Presynaptic Terminals / ultrastructure
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Rats
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Rats, Wistar
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Substantia Gelatinosa / cytology
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Substantia Gelatinosa / metabolism*
Substances
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Cholera Toxin
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Horseradish Peroxidase
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Capsaicin