Introduction dorsal root ganglion DRG [24–26,31,36,42] and axonally
Brain Research 883 2000 184–191 www.elsevier.com locate bres
Research report
Effects of substance P and calcitonin gene-related peptide on axonal transport in isolated and cultured adult mouse dorsal root ganglion
neurons
a , a
b c
d
Hiromi Hiruma , Ayako Saito , Takafumi Ichikawa , Yoriko Kiriyama , Sumio Hoka ,
e c
a
Tatsumi Kusakabe , Hirosuke Kobayashi , Tadashi Kawakami
a
Department of Physiology , Kitasato University School of Medicine, 1-15-1 Kitasato, Sagamihara 228-8555, Japan
b
Department of Biochemistry , Kitasato University School of Medicine, 1-15-1 Kitasato, Sagamihara 228-8555, Japan
c
Department of Medicine , Kitasato University School of Medicine, 1-15-1 Kitasato, Sagamihara 228-8555, Japan
d
Department of Anesthesiology , Kitasato University School of Medicine, 1-15-1 Kitasato, Sagamihara 228-8555, Japan
e
Department of Sport and Medical Science , Kokushikan University, 7-3-1 Nagayama, Tokyo 206-8515, Japan
Accepted 22 August 2000
Abstract
Substance P and calcitonin gene-related peptide CGRP released from primary sensory neurons are known to play important roles in nociception and nociceptive transmission. In the present study, we attempted to clarify the roles of these neuropeptides in the regulation of
axonal transport in sensory neurons. Cells were isolated from adult mouse dorsal root ganglia and cultured in F-12 medium containing fetal bovine serum for 48 h until their neurites were grown. These isolated and cultured DRG cells were mostly .98 small diameter
,25 mm and medium diameter, 25–40 mm in size, and were immunoreactive for substance P and CGRP 85.9 and 66.0 of total cells, respectively. Video-enhanced microscopy was applied to observe particles transported within neurites. Application of substance P 100
nM decreased the number of particles transported in both anterograde and retrograde directions in each of DRG neurons tested n55. The instantaneous velocities of individual particles transported in anterograde and retrograde directions were also reduced by substance P.
In contrast, a-CGRP 100 nM increased the number of particles transported in both directions in each of DRG neurons tested n55, and also increased the instantaneous velocities of particles transported bidirectionally. Application of b-CGRP 100–1000 nM did not elicit
any effect on axonal transport. Therefore, axonal transport in sensory neurons seems to be modulated by substance P and a-CGRP, both of which can be derived from its own and adjacent sensory neurons.
2000 Elsevier Science B.V. All rights reserved.
Theme : Development and regeneration
Topic : Axon guidance mechanisms and pathways
Keywords : Axonal transport; Dorsal root ganglion neuron; Substance P; Calcitonin gene-related peptide; Video-enhanced microscopy; Immuno-
cytochemistry
1. Introduction dorsal root ganglion DRG [24–26,31,36,42] and axonally
transported to the central and peripheral endings of sensory Neuropeptides such as substance P and calcitonin gene-
nerve fibers [5,12,23,34,35]. They are released from cen- related peptide CGRP play a critical role in regulating
tral terminals into the dorsal horn of the spinal cord to the inflammatory response in peripheral sensory neurons.
convey noxious information as synaptic transmitters [53]. These neuropeptides are synthesized in cell bodies of the
These neuropeptides are also released from peripheral terminals to induce extravasation, vasodilatation, inflam-
mation, and nociception [29,40,45].
Corresponding author. Tel.: 181-42-778-9159; fax: 181-42-778-
Axonal transport is recognized as a cellular function
9841. E-mail address
: hirumamed.kitasato-u.ac.jp H. Hiruma.
fundamental to synaptic transmission [11,18,50], axo-
0006-8993 00 – see front matter
2000 Elsevier Science B.V. All rights reserved. P I I : S 0 0 0 6 - 8 9 9 3 0 0 0 2 8 9 2 - 4
H . Hiruma et al. Brain Research 883 2000 184 –191
185
genesis [19], and synaptic formation [7]. Thus, axonal labelling immunofluorescent image, the immunostained
transport is considered to be closely related to the develop- cells were examined with an inverted Zeiss Axiomat
ment and function of the sensory nervous system as well as microscope Carl Zeiss, Oberkochen, Germany equipped
other neuronal systems. In the present study, we attempted with exciting filters 546 nm for rhodamine, 450–490 nm
to clarify the roles of major sensory neuropeptides, sub- for FITC and emission filters 590 nm for rhodamine,
stance P and CGRP, in the regulation of axonal transport in 515–565 nm for FITC. The number of immunoreactive
isolated and cultured adult mouse DRG neurons. neurons was determined under microscopic observation
and also by examining microphotographs. DRG neurons used for the experiments on axonal transport were also