Substance P immunoreactivity in the lumbar spinal cord of the turtle Trachemys dorbigni following peripheral nerve injury.

W.A Partata,L.L Xavier,A.M.R Krepsky,M Achaval,M Marques

doi:10.1590/s0100-879x2003000400015

W.A Partata, L.L Xavier + Show 3 more

Open Access

https://doi.org/10.1590/s0100-879x2003000400015

Copy DOI

Abstract

Immunoreactive substance P was investigated in turtle lumbar spinal cord after sciatic nerve transection. In control animals immunoreactive fibers were densest in synaptic field Ia, where the longest axons invaded synaptic field III. Positive neuronal bodies were identified in the lateral column of the dorsal horn and substance P immunoreactive varicosities were observed in the ventral horn, in close relationship with presumed motoneurons. Other varicosities appeared in the lateral and anterior funiculi. After axotomy, substance P immunoreactive fibers were reduced slightly on the side of the lesion, which was located in long fibers that invaded synaptic field III and in the varicosities of the lateral and anterior funiculus. The changes were observed at 7 days after axonal injury and persisted at 15, 30, 60 and 90 days after the lesion. These findings show that turtles should be considered as a model to study the role of substance P in peripheral axonal injury, since the distribution and temporal changes of substance P were similar to those found in mammals.

Highlights

Under ether-induced anesthesia [7], the right sciatic nerve was exposed and transected approximately 5 mm distal to the sciatic notch
The sections were treated with 3% hydrogen peroxide in 10% methanol for 30 min, washed with phosphate-buffered saline (PBS) for a further 30 min and incubated for 30 min in 3% normal goat serum in PBS containing 0.4% Triton X-100 (PBS-T)
A polyclonal antibody to rabbit substance P, whose specificity has been described in a previous report [8], diluted 1:800 in PBS-T, was applied to the sections which were incubated overnight with gentle shaking at 4oC

Summary

Introduction

Under ether-induced anesthesia [7], the right sciatic nerve was exposed and transected approximately 5 mm distal to the sciatic notch. Substance P immunoreactivity was found in the dorsal and ventral horns of the lumbar spinal cord, which was higher in gray matter than in white matter. These investigators only reported the presence of substance P immunoreactivity in synaptic field Ia, which invaded synaptic field III, and in the ventral horn limit.

Objectives

Results

Conclusion