Journal of chemical neuroanatomy
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J. Chem. Neuroanat. · Jan 2008
Differential galanin upregulation in dorsal root ganglia and spinal cord after graded single ligature nerve constriction of the rat sciatic nerve.
Single ligature nerve constriction (SLNC) is a newly developed animal model for the study of neuropathic pain. SLNC of the rat sciatic nerve induces pain-related behaviors, as well as changes in the expression of neuropeptide tyrosine and the Y(1) receptor in lumbar dorsal root ganglia (DRGs) and spinal cord. In the present study, we have analyzed the expression of another neuropeptide, galanin, in lumbar DRGs and spinal cord after different degrees of constriction of the rat sciatic nerve. ⋯ The highest numbers of galanin-IR neurons were detected 14 days after injury. In the dorsal horn of the spinal cord, medium and strong SLNCs induced a marked ipsilateral increase in galanin-like immunoreactivity in laminae I-II. These results show that galanin expression in DRGs and spinal cord is differentially regulated by different degrees of nerve constriction and further support its modulatory role on neuropathic pain.
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J. Chem. Neuroanat. · Jul 2010
Expression profile of multiple secretory phospholipase A(2) isoforms in the rat CNS: enriched expression of sPLA(2)-IIA in brainstem and spinal cord.
Phospholipases A(2) (PLA(2)) are enzymes which cleave the sn-2 ester bond in membrane phospholipids to release free fatty acids and lysophospholipids. The present study aimed to elucidate the expression profile of multiple secretory phospholipase A(2) (sPLA(2)) isoforms in the normal rat CNS with focus on sPLA(2)-IIA in the brainstem and spinal cord. Quantitative RT-PCR analysis showed that sPLA(2)-IB expression was low throughout the CNS, sPLA(2)-IIA expression was high in the brainstem and spinal cord, sPLA(2)-IIC expression was high in the cerebral neocortex, hippocampus and thalamus/hypothalamus, sPLA(2)-V expression was high in the olfactory bulb and cerebellum, and sPLA(2)-X was expressed at very low levels in the normal CNS. ⋯ Western blot analysis showed high level of sPLA(2)-IIA expression in the brainstem and cervical, thoracic and lumbar spinal segments but low level of expression in other parts of the brain. sPLA(2)-IIA was localized by immunohistochemistry to the spinal trigeminal and facial motor nuclei and dorsal- and ventral-horns of the spinal cord. The enzyme was found on the endoplasmic reticulum of neuronal cell bodies and small diameter dendrites or dendritic spines at electron microscopy. The expression of sPLA(2)-IIA in the dorsal horn and spinal trigeminal nucleus is consistent with previous results which showed an important role of CNS sPLA(2) in nociceptive transmission.
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J. Chem. Neuroanat. · Jan 2014
Fifth lumbar spinal nerve injury causes neurochemical changes in corresponding as well as adjacent spinal segments: a possible mechanism underlying neuropathic pain.
Previous investigations of the anatomical basis of the neuropathic-like manifestations in the spinal nerve ligation animal model have shown that the central terminations of the unmyelinated primary afferents of L5 spinal nerve are not restricted to the corresponding L5 spinal segment, and rather extend to two spinal segments rostrally and one segment caudally where they intermingle with primary afferents of the adjacent L4 spinal nerve. The aim of the present study was to investigate the neurochemical changes in the dorsal horn of the spinal cord and DRGs after L5 nerve injury in rats. In the first experiment, the right L5 nerve was ligated and sectioned for 14 days, and isolectin B4 (IB4, a tracer for unmyelinated primary afferents) was injected into the left L5 nerve. ⋯ Similar neurochemical changes were observed only in the corresponding L5 DRG with minimal effects observed in L3, L4 and L6 DRGs. Although, L5 nerve injury caused an up-regulation in NPY, no change in SP and CGRP immunoreactivity was observed in ipsilateral garcile nucleus. These neuroplastic changes in the dorsal horn of the spinal cord, in the adjacent uninjured territories of the central terminations of the adjacent uninjured nerves, might explain the mechanism of hyperalgesia after peripheral nerve injury.
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J. Chem. Neuroanat. · Jul 2011
Altered expression of neuronal tryptophan hydroxylase-2 mRNA in the dorsal and median raphe nuclei of three genetically modified mouse models relevant to depression and anxiety.
Depression and anxiety are among the leading causes of societal burden. Abnormalities in 5-hydroxytryptamine (5-HT; serotonin) neurotransmission are known to be associated with depressive and anxiety symptoms. The rostral projections of brainstem dorsal (DRN) and median (MRN) raphe nuclei are the main sources of forebrain 5-HT. ⋯ Thus, there were significant decreases in TPH2 transcript levels in 5-HT transporter (5-HTT)-/- mutant mice, whereas increases were observed in the vesicular glutamate transporter 1 hemi knock out (VGLUT1+/-) and cannabinoid receptor 1 mutant (CB1R-/-) mice. Based on these findings, we suggest that TPH2 mRNA expression is under the influence of multiple messenger systems in relation to presynaptic and/or postsynaptic feedback control of serotonin synthesis that, 5-HTT, VGLUT1 and CB1R seem to be involved in these feedback mechanisms. Finally, our data are in line with previous reports suggesting that TPH2 activity within different raphe subregions is differentially regulated under specific conditions.
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J. Chem. Neuroanat. · Jan 1989
Geniculo-geniculate projection of enkephalin and neuropeptide Y containing neurons in the intergeniculate leaflet of the thalamus in the rat.
Geniculo-geniculate projections of immunoreactive neurons for gamma-aminobutyric acid (GABA), leucine-enkephalin (ENK), neuropeptide Y (NPY) and substance P (SP) in the intergeniculate leaflet (IGL) and ventral lateral geniculate nucleus (VLG) of the rat were examined by using a combination of retrograde tracing method and immunocytochemistry. After injection of the fast blue (FB) dye into the IGL and VLG, many ENK immunoreactive neurons, and some NPY immunoreactive neurons were labelled by FB dye in the contralateral IGL. ⋯ These findings suggested that ENK is one major component of the neuroactive substances in the geniculo-geniculate projection, and NPY also contributes partly to this projection. Furthermore, the unilateral destruction of the IGL and VLG showed a marked loss of the NPY immunoreactive fibres and a slight loss of the ENK immunoreactive fibres in the bilateral suprachiasmatic nuclei.