Neuroreport
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The aim of this study was to investigate the expression of total calcium/calmodulin-dependent protein kinase II (CaMKII) and its phosphorylated α isoform in the dorsal horn of the spinal cord in an animal model of long-term diabetes. Diabetes was induced in Sprague-Dawley rats using 55 mg/kg streptozotocin, and expression of total CaMKII, the phosphorylated α-CaMKII isoform, and isolectin B4 was analyzed by immunohistochemical analysis in the dorsal horn of the spinal cord 6 and 12 months after diabetes induction. Results were compared with those for control rats of the same age. ⋯ The expression of activated α-CaMKII 12 months after diabetes induction was most pronounced in laminae I-VI of the dorsal horn, not corresponding with the highest expression of isolectin B4 in laminae I-III. Increased expression of CaMKII in the dorsal horn during long-term diabetes could be involved in the development of neuropathic symptoms in diabetes. The expression pattern of CaMKII during long-term diabetes indicates that it affects the entire sensory input.
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Previous reports suggest that sex differences may exist in dreaming under anesthesia, but their results were inconclusive. The current study explored sex differences in the incidence and content of dreams during short propofol sedation for upper gastrointestinal endoscopy and investigated whether sex differences or dream content affect patient satisfaction with sedation. A total of 200 patients (100 men and 100 women) undergoing upper gastrointestinal endoscopy participated in this study. ⋯ Men reported dreaming more frequently and had a higher incidence of recall for their dream narratives. In particular, men reported significantly more positive emotional content, less negative emotional content, and more meaningful content. Dreamer satisfaction with sedation was not influenced by sex or dream content.
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In this study, we investigated how ipsilateral motor cortex (M1) activation during unimanual hand movements and hemispheric asymmetry changed after motor skill learning. Eleven right-handed participants preformed a two-ball-rotation motor task with the right and the left hand, separately, in all experimental sessions. Before and after exercise sessions, the degree of ipsilateral M1 activation during brief execution of the motor task was measured as changes in the size of motor-evoked potentials (MEPs) of the thenar and the first dorsal interosseous muscle of the nontask hand using transcranial magnetic stimulation. ⋯ After exercise, facilitation of MEPs of the nontask hand during the motor task was significantly reduced for the right hand (thenar: P=0.014, first dorsal interosseous: P=0.022) but not for the left hand. We conclude that ipsilateral M1 activation, associated with a complex motor task, is first symmetrical in both hemispheres. However, on exercise, ipsilateral activation is reduced only in left M1, indicating a stronger learning-dependent modification of motor networks within the left hemisphere.
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Although spinal neurons expressing BB2 bombesin receptors are suggested to be involved in itch transmission, their role in pathological itch remains unknown. Because itch is often observed in patients with herpes zoster, we examined the role of BB2 receptor-expressing spinal neurons in herpes-associated itch in mice. ⋯ Intrathecal administration of the BB2 receptor antagonist Leu13-ψ-(CH2NH)Leu14-bombesin decreased BB2 receptor agonist GRP(18-27)-induced scratching in naive mice but not herpes-associated scratching. The present results suggest that BB2 receptor-expressing spinal neurons transmit herpes-associated itch by BB2 receptor-independent signaling.
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The neuropathic pain that occurs after peripheral nerve injury may be related to abnormal central activity. The present experiments investigated the effects of MK-801 [N-methyl-D-aspartate (NMDA) receptor antagonist] on neuropathic pain behaviors and microglial activity in rats. Neuropathic pain was produced by L5 spinal nerve ligation of rats. ⋯ Microglial activity was measured by observing changes in immunoreactivity with a microglia marker, OX-42. The MK-801, at a dose of 3 or 30 µg/5 µl, injection group showed higher neuropathic pain threshold and reduction of microglial activity. These results suggest that neuropathic pain behaviors following L5 spinal nerve ligation may be related to altered activity of the microglia involving the NMDA receptor, and chronological changes of microglial activation by MK-801 are related to maintenance of mechanical allodynia.