Brain research. Molecular brain research
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Brain Res. Mol. Brain Res. · May 2000
Seizures and sensory stimulation result in different patterns of brain derived neurotrophic factor protein expression in the barrel cortex and hippocampus.
Brain-derived neurotrophic factor (BDNF) is important for the development and trophic support of neurons, and may be involved in controlling axonal sprouting and synaptic plasticity. In order to investigate the activity-dependent regulation of the BDNF gene, BDNF expression was examined within the rat somatosensory cortex (SSC) and hippocampus following vibrissae stimulation, kainic acid induced seizure, and pentylenetetrazol (PTZ) induced seizure. The specific goals of this study were to determine the time course and magnitude of BDNF's activity-dependent expression, and to compare the expression patterns of three commonly used neuronal activation paradigms. ⋯ Finally, whisker stimulation resulted in an unexpected increase in BDNF mRNA and protein levels within the hippocampus. These results suggest specific types of neuronal activity can regulate gene expression differently. Furthermore, temporal and spatial differences between the expression of BDNF protein and mRNA levels suggest that the BDNF gene is regulated at the level of translation as well as transcription.
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We examined developmental changes of orexins/hypocretins and their receptors (OX1R and OX2R) in the rat hypothalamus from postnatal day 0 to 10 weeks, using in situ hybridization histochemistry for the prepro-orexin, OX1R and OX2R mRNAs and immunohistochemistry for orexin-A and orexin-B. The prepro-orexin mRNA was weakly detected in the lateral hypothalamic area (LHA) from days 0 to 15. Orexin-A- and -B-like immunopositive cells and fibers were not detected from days 0 to 10, but they were observed after day 15. ⋯ Next, we examined the effects of milk deprivation and intraperitoneal (i.p.) administration of leptin on the hypothalamic prepro-orexin mRNA in pups. Although 24-h milk deprivation did not affect the level of the prepro-orexin mRNA at days 5 and 10, i.p. administration of leptin from days 0 to 3 caused a significant increase in the prepro-orexin mRNA on days 5 and 10. These results suggest that the development of orexins may be associated with developmental changes such as increase of leptin, weaning, feeding and sleep/wakefulness states.