Experimental neurology
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Experimental neurology · Mar 2009
Treadmill training enhances the recovery of normal stepping patterns in spinal cord contused rats.
Treadmill training is known to improve stepping in complete spinal cord injured animals. Few studies have examined whether treadmill training also enhances locomotor recovery in animals following incomplete spinal cord injuries. In the present study, we compared locomotor recovery in trained and untrained rats that received a severe mid-thoracic contusion of the spinal cord. ⋯ In contrast, untrained rats executed step cycles that consisted of fast, kick-like movements during forward swing. These findings indicate that spinal cord contused rats can generate partial weight bearing stepping in the absence of treadmill training. The findings also suggest that the effect of treadmill training is to restore normal patterns of hindlimb movements following severe incomplete spinal cord injury in rats.
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Experimental neurology · Mar 2009
Basic fibroblast growth factor-enhanced neurogenesis contributes to cognitive recovery in rats following traumatic brain injury.
Stem/progenitor cells reside throughout the adult CNS and are actively dividing in the subventricular zone (SVZ) and the dentate gyrus (DG) of the hippocampus. This neurogenic capacity of the SVZ and DG is enhanced following traumatic brain injury (TBI) suggesting that the adult brain has the inherent potential to restore populations lost to injury. This raises the possibility of developing strategies aimed at harnessing the neurogenic capacity of these regions to repair the damaged brain. ⋯ Moreover, following bFGF infusion, a greater number of the newly generated cells survived to 4 weeks post-injury, with the majority being neurons. Additionally, animals infused with bFGF showed significant cognitive improvement. Collectively, the current findings suggest that bFGF-enhanced neurogenesis contributes to cognitive recovery following TBI.
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Experimental neurology · Mar 2009
Secondary degeneration of the optic nerve following partial transection: the benefits of lomerizine.
Secondary degeneration is a form of 'bystander' damage that can affect neural tissue both nearby and remote from an initial injury. Partial optic nerve transection is an excellent model in which to unequivocally differentiate events occurring during secondary degeneration from those resulting from primary CNS injury. We analysed the primary injury site within the optic nerve (ON) and intact areas vulnerable to secondary degeneration. ⋯ Lomerizine protected RGCs from secondary death at 4 weeks but did not fully restore behavioural function (optokinetic nystagmus). We conclude that blockade of calcium channels is neuroprotective and limits secondary degenerative changes following CNS injury. However such an approach may need to be combined with other treatments to ensure long-term maintenance of full visual function.
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Experimental neurology · Mar 2009
TIMP-3 and MMP-3 contribute to delayed inflammation and hippocampal neuronal death following global ischemia.
Hippocampal neuronal death following transient global ischemia in the mouse takes days to occur, providing a potential timeframe for therapeutic intervention. Since matrix metalloproteinase-3 (MMP-3) enhances inflammation and tissue inhibitor of metalloproteinases-3 (TIMP-3) promotes apoptosis in ischemia, we hypothesized that they are involved in neuronal death secondary to transient global ischemia. Timp-3 knockout (T3KO) and wild type (T3WT) mice underwent 30 min bilateral carotid artery occlusion (BCAO), which causes hippocampal neuronal death 7 days after reperfusion. ⋯ To see if TIMP-3 and MMP-3 cell death pathways were independent, we blocked MMPs with the broad-spectrum MMP inhibitor, BB-94, on days 3 through 6 of reperfusion in T3WT and T3KO mice. BB-94 rescued hippocampal neurons at 7 days in both T3WT and T3KO mice, but significantly fewer neurons died in T3KO mice treated with BB-94. Our results indicate a novel additive role for TIMP-3 and MMP-3 in delayed neuronal death, and show that delayed treatment with MMP inhibitors can be used to reduce hippocampal death.
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Experimental neurology · Mar 2009
Enhanced pronociception by amygdaloid group I metabotropic glutamate receptors in nerve-injured animals.
Peripheral neuropathy has been associated with structural and functional changes of the amygdala, a key player in emotions. Here we study whether peripheral neuropathy influences pain regulation by the amygdala. For this purpose, we determined discharge rates of presumably pro- and antinociceptive pain-regulatory neurons in the rostral ventromedial medulla (RVM) following microinjection of various glutamatergic compounds into the central nucleus of the amygdala. ⋯ CHPG, an mGluR(5) agonist, failed to influence ON-cell activity and DHPG failed to influence activity of presumably antinociceptive RVM OFF-cells. Amygdaloid administration of DHPG increased and that of CPCCOEt decreased affective pain-related behavior in nerve-injured animals. The results suggest that following nerve injury, the amygdaloid group I mGluR, particularly subtype mGluR(1), has an enhanced pronociceptive effect providing a potential mechanism for emotional enhancement of pain in peripheral neuropathy.