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Abstract: Tissue and nerve damage can result in chronic pain. Yet, chronic pain after cesarean delivery is remarkably rare in women and hypersensitivity from peripheral nerve injury in rats resolves rapidly if the injury occurs in the puerperium. Little is known regarding the mechanisms of this protection except for a reliance on central nervous system oxytocin signaling. Here we show that the density of inhibitory noradrenergic fibers in the spinal cord is greater when nerve injury is performed in rats during the puerperium, whereas the expression of the excitatory regulators dynorphin A and neuregulin-1 in the spinal cord is reduced. The puerperium did not alter spinal cord microgial and astrocyte activation. Astrocyte activation, as measured by glial fibrillary acidic protein (GFAP) expression, was not evident in female rats with injury, regardless of delivery status suggesting sex differences in spinal astrocyte activation after injury. These results suggest a change in the descending inhibitory/facilitating balance on spinal nociception neurotransmission during the puerperium, as mechanisms for its protective effect against injury-induced hypersensitivity. [Copyright &y& Elsevier]

Abstract: Acetylcholine reduces nociceptive input in part by activating inhibitory M2 muscarinic receptors on primary sensory neurons, and acetylcholinesterase inhibitors and muscarinic agonists produce analgesia in humans and animals. M2 muscarinic receptors are upregulated in animals with diabetic neuropathy, but their level of expression and function after peripheral nerve injury has not been previously examined. This study tested, using intracellular Ca2+ response to membrane depolarization, the effect of the M2 muscarinic receptor agonist bethanechol on individual dorsal root ganglion cells from normal and L5-6 spinal nerve-ligated rats, followed by M2 muscarinic receptor immunostaining. We also examined functional transient receptor potential for vanilloids-1 activity by determining intracellular Ca2+ response evoked by capsaicin in M2 muscarinic receptor immunoreactive cells. In normal dorsal root ganglion cells, bethanechol inhibited the Ca2+ response in a concentration-related fashion, and this inhibition was blocked by the M2 muscarinic receptor antagonist gallamine. Cells expressing M2 muscarinic receptors by immunostaining were significantly inhibited by bethanechol, whereas those lacking positive staining were not. The proportion of studied dorsal root ganglion neurons with positive M2 muscarinic receptor staining increased significantly in the injured ipsilateral L5-6 and the uninjured ipsilateral L4 ganglia, but not in the contralateral dorsal root ganglion neurons compared with normals. In contrast, the proportion of neurons responding to capsaicin significantly decreased in the injured ipsilateral L5-6 dorsal root ganglion cells. These results suggest that inhibitory M2 muscarinic receptors are upregulated in small- and medium-sized axotomized dorsal root ganglion neurons and their uninjured neighbors following nerve injury, and may represent an appropriate target for analgesia in this setting. [Copyright &y& Elsevier]

Abstract: We present the XMM-Newton observation of an X-ray faint cluster of galaxies A1674. Three regions of diffuse X-ray emission (A1674-NE, A1674-Center, and A1674-West) are detected from A1674. We measure the temperature and metal abundance of this diffuse emission. The diffuse X-ray emission from A1674-Center can be characterized by a thermal plasma with a characteristic temperature of and a metal abundance of 0.07(<0.2) Z ⊙. The low metal abundance of A1674-Center suggests that not enough metals are supplied from member galaxies. [Copyright &y& Elsevier]

Abstract: We investigate the dark matter distributions in the central region of two clusters of galaxies (A1835 and MKW3S) using Chandra data. N-body simulations in the standard cold dark matter (CDM) model predict the dark matter distribution shows a cuspy dark matter profile: ρ(r)∝rα, with α in the range 1–2, while observations of dwarf and low surface brightness galaxies seem to favor the presence of a relatively flat core: 0<α<1. To investigate the dark matter distributions in the central region of clusters of galaxies, we analyze the Chandra data of A1835 and MKW3S with a deprojection method. We derive the mass profiles without the assumption of analytical models. We examine the inner slope of derived mass profiles assuming the dark matter profile is described with a power-law expression. The values of the slope α are 0.95±0.10 for A1835 and 1.33±0.12 for MKW3S within the radius of 200 kpc. These are consistent with the result of the CDM simulations. However, within the radius of 100 kpc, the value of α is less than unity for A1835 (0.47±0.31). Our result implies that the central dark matter profile of some clusters cannot be described by CDM halos. [Copyright &y& Elsevier]

We propose a new type of wide band X-ray imaging spectrometer as a focal plane detector of the super mirror onboard on future X-ray missions including post Astro-E2. This camera is realized by the hybrid of back illumination CCDs and a back supportless CCD for 0.05–10 keV band, and a Micro Pixel Gas Chamber detecting X-rays at 10–80 keV. [Copyright &y& Elsevier]