A polyclonal antibody to rabbit substance P (a gift from Dr. The sections were then treated with 3% hydrogen peroxide in 10% methanol for 30 min, washed with 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).
#Image pro plus dendrite measure serial
Coronal serial sections (50 µm) were obtained with a cryostat (Leitz) and collected in cold phosphate-buffered saline (PBS). The lumbar spinal cord was quickly dissected out, immersed in the same fixative for 2 h and then cryoprotected in 15 and 30% sucrose solutions in phosphate buffer at 4✬. On the final day of the experiment, both operated and control turtles were anesthetized (25 mg/kg Thionembutal, intraperitoneally) and perfused through the heart with cold saline solution followed by 4% paraformaldehyde in 0.1 M sodium phosphate buffer, pH 7.4. Groups of three turtles of both sexes, weighing 300-400 g, were sacrificed 7, 15, 30, 60 and 90 days later. In this nerve transection, a 2-mm segment of the nerve was removed to ensure that the transection was complete.
Under ether-induced anesthesia (7), the right sciatic nerve was exposed and transected approximately 5 mm distal to the sciatic notch. Therefore, the aim of this study was to determine the effects of sciatic nerve transection on substance P immunoreactive fibers in the lumbar spinal cord of the turtle Trachemys dorbigni. Previous studies demonstrated substance P immunoreactivity in the turtle central nervous system (5,6) however, the effects of peripheral axotomy on substance P distribution have not been studied. The chemical structure of substance P is highly conserved in non-mammalian species, and is also found in turtles, animals considered phylogenetically related to the extinct theropsids from which mammals arose (4). In rats, peripheral nerve sectioning leads to a marked quantitative decrease in the nerve of substance P, a peptide of 11 amino acids that is present in small primary afferents and plays an important role in pain sensation (2,3). Peripheral nerve injury may result in significant changes in neuropeptide production and the development of neuropathic pain behavior (1). Key words: Substance P immunoreactivity, Axonal injury, Spinal cord, Turtle, Trachemys dorbigni
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. The changes were observed at 7 days after axonal injury and persisted at 15, 30, 60 and 90 days after the lesion. 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. Other varicosities appeared in the lateral and anterior funiculi. 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. In control animals immunoreactive fibers were densest in synaptic field Ia, where the longest axons invaded synaptic field III. Immunoreactive substance P was investigated in turtle lumbar spinal cord after sciatic nerve transection.
Achaval 2ĭepartamentos de 1Fisiologia and 2Ciências Morfológicas, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brasil
Substance P immunoreactivity in the lumbar spinal cord of the turtle Trachemys dorbigni following peripheral nerve injury Braz J Med Biol Res, April 2003, Volume 36(4) 515-520 (Short Communication)
0 kommentar(er)
