Neuroreport
-
Hyperbaric oxygen (HBO2) therapy induces analgesia in various conditions of pain in humans. In mice, HBO2 treatment evokes an acute antinociceptive response in the abdominal constriction test. ⋯ The antinociceptive effect was also significantly reduced in mice homozygous for a defective neuronal NOS gene. On the basis of these results, we conclude that neuronal NO is critical in the expression of the acute antinociceptive effect of HBO2.
-
Event-related potentials were recorded to examine the electrophysiologic correlates of the evaluation of possible answers provided during a semantic, a numeric, and a figure inference task. We examined two conditions: the probe stimulus given was what participants initially generated (Correct answer) or it was unexpected and incorrect (Unexpected Incorrect answer). ⋯ The generator of N320 effect was localized near the anterior cingulate cortex. The N320 effect, therefore, reflects an expectation violation while participants performed semantic, numeric, or figure inference task.
-
In an earlier study, we reported the antinociceptive effects of a special repetitive transcranial magnetic stimulation paradigm: continuous theta-burst stimulation (cTBS), when applied to human motor cortex. Here, we investigated whether the reduced subjective pain perception of 10 healthy individuals could be measured by changes in laser-evoked potentials, a reflection of pain related activations in the operculoinsular and midcingulate cortex. ⋯ However, both pain ratings and laser-evoked potential amplitudes were reduced after real and sham cTBS. When compared with sham stimulation, cTBS resulted in a significantly greater diminution of pain ratings and N2-P2 amplitudes on the hand contralateral to the site of motor cortex stimulation.
-
Percutaneous inoculation of mice with herpes simplex virus type-1 produces marked dynamic allodynia in the zosteriform dermatome. In this study, we examined the electrophysiological excitability of the wide-dynamic range neuron in the spinal dorsal horn and the tibial nerve in response to mechanical (brush, punctum, and pinch) stimuli in mice with herpetic allodynia. ⋯ The responses of the tibial nerve to all kinds of mechanical stimuli examined were decreased. These results suggest that dynamic allodynia in the affected dermatome is because of the increased excitability of wide-dynamic range neurons, but not primary afferents, to brush stimulation.
-
Gangliosides, GM3 and GM1, are suggested to accelerate the deposition of the amyloid beta-protein as amyloid angiopathy and senile plaques, respectively, in the Alzheimer brain. We investigated the profile of amyloid deposition in the brains of transgenic mice expressing a mutant amyloid precursor protein with a disrupted GM2 synthase gene, in which GM3 accumulates whereas GM1 is lacking. ⋯ Furthermore, formation of severe dyshoric-form amyloid angiopathy, in which amyloid extended from the blood vessel walls deeply into the surrounding parenchyma was observed. Our results indicate that the expression of gangliosides is a critical determinant for the amyloid pathology in the Alzheimer brain.