Neuroscience letters
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Neuroscience letters · Nov 2007
Spinal cord stimulation modulates activity of lumbosacral spinal neurons receiving input from urinary bladder in rats.
The aim of this study was to determine whether spinal cord stimulation (SCS) modulates activity of lumbosacral spinal neurons receiving input from the urinary bladder. Extracellular potentials of L6-S2 spinal neurons were recorded in pentobarbital anesthetized, paralyzed and ventilated male rats. ⋯ SCS affected spinal neurons with either high- or low-threshold responses to UBD. These results suggested that SCS might have a potential therapeutic effect for patients with hypersensitivity and/or pain of cystitis and other urinary bladder disorders.
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Neuroscience letters · Nov 2007
Organization of a unique net-like meshwork of CGRP+ sensory fibers in the mouse periosteum: implications for the generation and maintenance of bone fracture pain.
Although bone fracture frequently results in significant pain and can lead to increased morbidity and mortality, it is still not clearly understood how sensory neurons are organized to detect fracture pain. In the present report we focused on the periosteum, as this thin tissue is highly innervated and tightly adherent to the outer surface of bone. To define the organization and distribution of the sensory and sympathetic fibers in the mouse femoral periosteum, we used whole-mount preparations, transverse sections, immunofluoresence and laser scanning confocal microscopy. ⋯ In contrast, the majority of CGRP+ and NF200+ sensory fibers in both layers lack a clear association with CD31+ blood vessels and appear to be organized in a dense net-like meshwork to detect mechanical distortion of periosteum and bone. This organization would explain why stabilization/fixation causes a marked attenuation of movement-evoked fracture pain. Understanding the organization, plasticity and molecular characteristics of sensory and sympathetic nerve fibers innervating the skeleton may permit the development of novel mechanism-based therapies for treating non-malignant skeletal pain.
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Neuroscience letters · Nov 2007
Increased invasion of ED-1 positive macrophages in both ipsi- and contralateral dorsal root ganglia following unilateral nerve injuries.
There is an increasing evidence that unilateral nerve injury induces cellular and molecular changes in the associated DRG not only on the ipsilateral but also in the contralateral side. In this investigation, ED-1+ macrophages were quantified by image analysis in the naïve L5 DRG (nDRG) and compared with the ipsi- and contralateral ones 2 and 4 weeks after unilateral sciatic nerve ligature and ventral root transection (VRT). A few ED-1+ macrophages were found in nDRG but not closely associated with the neuronal bodies. ⋯ Our experiments indicate that a significantly higher number of ED-1+ macrophages remained in both ipsi- and contralateral DRG up to 4 weeks from nerve injury. Based on results from different models of nerve injury, we suggest that more than one mechanism operates to stimulate the invasion of ED-1+ macrophages into the DRG including retrograde transport of factors produced during Wallerian degeneration or their delivery by blood flow. Signaling for macrophage invasion into DRG contralateral to nerve injury may be mediated by lost motoneurons or by interneurones.