Brain research
-
In this study, we evaluated the expression of MCP-1 in the rat dorsal root ganglion (DRG) and spinal cord following axotomy and chronic constriction injury (CCI) of the sciatic nerve and L5 spinal nerve ligation (L5 SNL) using an immunohistochemical approach. MCP-1 expression in the DRG peaked and declined before the full onset of pain hypersensitivity following nerve injury. Spinal expression of MCP-1 peaked when mechanical allodynia was maximal, but then declined rapidly despite the remarkable persistence of mechanical allodynia. ⋯ Despite increased MCP-1 in small and large DRG neurons, a remarkable increase in MCP-1-IR terminals was observed in the spinal superficial laminae following CCI and L5SNL, but not following axotomy; however, in the deeper laminae, a considerable increase in MCP-1-IR terminals, which may originate from the large and injured L5 DRG neurons, was found after L5 SNL. Our results demonstrate that MCP-1 synthesized in DRG neurons may or may not be transported to the spinal cord depending on the type of peripheral nerve injury. Additionally, increased MCP-1 in both intact L4 and injured L5 DRG neurons may contribute to neuropathic pain hypersensitivity following L5 SNL.
-
Rehabilitation improves recovery after intracerebral hemorrhage (ICH) in rats. In some cases, brain damage is attenuated. In this study, we tested whether environmental enrichment (EE) combined with skilled reach training improves recovery and lessens brain injury after ICH in rats. ⋯ Unexpectedly, REHAB treatment lessened spontaneous use of the contralateral-to-ICH limb at 4 (p=0.045) and 6 weeks (p=0.041). In summary, the combination of EE and reach training significantly attenuates lesion volume (striatal injury) while improving skilled reaching and walking ability. These findings encourage the use of early rehabilitation therapies in patients suffering from basal ganglia hemorrhaging.
-
Secondary brain damage plays a critical role in the outcome of patients with traumatic brain injury (TBI). The multiple mechanisms underlying secondary brain damage, including posttraumatic cerebral ischemia, glutamate excitotoxicity, oxidative stress, calcium overload and inflammation, are associated with increased mortality and morbidity after head injury. TBI is documented to have detrimental effects on mitochondria, such as alterations in glucose utilization and the depression of mitochondrial oxidative phosphorylation. ⋯ The differences may indicate the degree of metabolic and physiologic dysfunction. Our results will better define the roles of gene expression and metabolic function in long-term prognosis and outcome after TBI. With a considerable understanding of post-injury mitochondrial dysfunction, therapeutic interventions targeted to the mitochondria may prevent secondary brain damage that leads to long-term cell death and neurobehavioral disability.
-
A subset of German function verbs can be used either in a full, concrete, 'heavy' ("take a computer") or in a more metaphorical, abstract or 'light' meaning ("take a shower", no actual 'taking' involved). The present magnetoencephalographic (MEG) study explored whether this subset of 'light' verbs is represented in distinct cortical processes. A random sequence of German 'heavy', 'light', and pseudo verbs was visually presented in three runs to 22 native German speakers, who performed lexical decision task on real versus pseudo verbs. ⋯ Thus, 'heavy' versus 'light readings' of verbs already modulate early posterior visual evoked response even when verbs are presented in isolation. This response becomes clearer in the disambiguating contextual condition. This type of study shows for the first time that language processing is sensitive to representational differences between two readings of one and the same verb stem.
-
Tolerance to peripheral antinociception after chronic exposure to systemic morphine was assessed in mice with chronic CFA-inflammation; cross-tolerance to locally administered mu, delta and kappa-opioid agonists and levels of beta-arrestins in the injured paw, were also evaluated. Tolerance was induced by the subcutaneous implantation of a 75 mg morphine-pellet, and antinociception evaluated with the Randall-Selitto test, 5 min after the subplantar injection of morphine, fentanyl, buprenorphine, DPDPE, U-50488H or CRF. Experiments were performed in the absence and presence of CFA-inflammation, in animals implanted with a morphine or placebo pellet. ⋯ Tolerance did not alter beta-arrestins, but partially prevented the increase induced by inflammation. The results suggest that peripheral beta-arrestins could facilitate peripheral OR-desensitization and tolerance development. Clinically, the experiments could be useful to establish the effectiveness of local opioid administration in patients with musculoskeletal pain, chronically receiving morphine analgesia.