Premium
Overexpression of nerve growth factor in epidermis disrupts the distribution and properties of sympathetic innervation in footpads
Author(s) -
Guidry Guy,
Landis Story C.,
Davis Brian M.,
Albers Kathryn M.
Publication year - 1998
Publication title -
journal of comparative neurology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.855
H-Index - 209
eISSN - 1096-9861
pISSN - 0021-9967
DOI - 10.1002/(sici)1096-9861(19980406)393:2<231::aid-cne7>3.0.co;2-3
Subject(s) - catecholaminergic , nerve growth factor , cholinergic , sensory system , biology , axon , neuroscience , plexus , brainstem , sympathetic nervous system , catecholaminergic cell groups , sensory neuron , cholinergic neuron , anatomy , endocrinology , catecholamine , biochemistry , receptor , blood pressure
Sympathetic and sensory neurons form distinct axonal arborizations in several peripheral targets. The developmental mechanisms responsible for partitioning sympathetic and sensory axons between potential target tissues are poorly understood. We have used rodent footpads to study this process because three populations of peripheral axons innervate topographically segregated targets in the footpad; cholinergic sympathetic axons innervate sweat glands, noradrenergic sympathetic axons innervate blood vessels, and sensory axons form a plexus at the epidermal/dermal junction. To examine how nerve growth factor (NGF), a trophic and survival factor for sympathetic and some sensory neurons, may contribute to the generation of the patterned distribution of axons among targets, we studied transgenic mice (K14‐NGF mice) in which NGF expression was significantly increased in the epidermis. Whereas the temporal sequence in which sensory and sympathetic fibers arrived in the footpad was not affected, the normal partitioning of axons between target tissues was disrupted. The two sympathetic targets in footpads, sweat glands, and blood vessels lacked substantial innervation and instead a dense plexus of catecholaminergic sympathetic fibers was found commingled with sensory fibers in the dermis. Those sympathetic fibers present in sweat glands expressed an abnormal dual catecholaminergic/cholinergic phenotype. Our findings indicate that overexpression of NGF in skin interferes with the segregation of sensory and sympathetic axonal arbors and suggests a role for target‐derived NGF in the establishment of distinct axonal territories. Our data also suggest that by determining where axon arbors form, NGF can indirectly influence the phenotypic properties of sympathetic neurons. J. Comp. Neurol. 393:231–243, 1998. © 1998 Wiley‐Liss, Inc. This article is a US Government work and, as such, is in the public domain in the United States of America.