Neuroscience
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The firing pattern of individual neurons is an important element for information processing and storing. During the first weeks of development, there is a transitional period during which CA1 pyramidal neurons display burst-spiking behavior in contrast to the adult regular-firing pattern. Spike after-depolarizations (ADPs) constitute a major factor underlying burst-spiking behavior. ⋯ In agreement with the development of the ADP waveform and burst-spiking behavior, voltage-clamp experiments in dissociated pyramidal neurons showed an increase in the LVA calcium current in P16-19 vs P9-12. Finally, we found that a reduction of extracellular calcium levels decreases the percentage of burst-spiking cells due to a reduction in the active component of the ADP. We conclude that a major contribution of LVA calcium channels to ADP determines the bursting capability of CA1 pyramidal neurons during a transitional postnatal period in contrast to adulthood.
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In the mouse, odorant receptor proteins (ORs) are G-protein-coupled receptors expressed in mature olfactory sensory neurons (OSNs) of the main olfactory epithelium (MOE). ORs mediate odorant reception at the level of the OSN cilia. Most of the ∼1100 OR genes in the mouse genome are expressed, at the RNA level, in mature OSNs. ⋯ The number of OSNs immunoreactive for the MOR28/Olfr1507 antibody is greater in C57BL/6J than in 129S6/SvEvTac wild-type mice. Taken together, our results are encouraging: 20-30% of these commercially available antibodies are informative in immunohistochemical analyses of the mouse MOE. The commercial availability of these antibodies should facilitate the study of OR proteins in the MOE and the olfactory bulb, and the replicability of results in the literature.
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Multiple sclerosis (MS) is an autoimmune disease in which more than 70% of patients experience visual disturbance as the earliest symptoms. Lysolecithin (LPC)-induced focal demyelination model has been developed to evaluate the effects of different therapies on myelin repair improvement. In this study, the effects of pregabalin administration on myelin repair and glial activation were investigated. ⋯ Luxol fast blue staining and immunostaining against PLP, as mature myelin marker, showed that myelin repair was improved in animals received pregabalin treatment. In addition, pregabalin effectively reduced the expression of GFAP and Iba1 as activated glial markers in optic chiasm. The present study indicates that pregabalin administration enhances myelin repair and ameliorates glial activation of optic chiasm following local injection of LPC.
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Glutamate is the most abundant excitatory neurotransmitter in the central nervous system, and is stored and released by both neurons and astrocytes. Despite the important role of glutamate as a neurotransmitter, elevated extracellular glutamate can result in excitotoxicity and apoptosis. Monosodium glutamate (MSG) is a naturally occurring sodium salt of glutamic acid that is used as a flavor enhancer in many processed foods. ⋯ Indeed, we found that exposure to MSG from postnatal days 4 through 10 resulted in significantly fewer neurons in the cochlear nuclei and SOC and significant dysmorphology in surviving neurons. Moreover, we found that neonatal MSG exposure resulted in a significant decrease in the expression of both calretinin and calbindin. These results suggest that neonatal exposure to MSG interferes with early development of the auditory brainstem and impacts expression of calcium binding proteins, both of which may lead to diminished auditory function.
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Human Albumin is a unique pleiotropic protein with multiple properties. Previous clinical and laboratory studies have indicated a possible beneficial effect of Albumin in subarachnoid hemorrhage (SAH). The present study aimed to further define the preclinical characteristics of Albumin. ⋯ In female rats and spontaneously hypertensive rats, Albumin likewise improved neurological outcomes and early brain injury. In conclusion, Albumin could reduce both cerebral lesions and functional deficits in the early stage of SAH. The beneficial regimen occurs within a favorable therapeutic window and is reproducible in different high-risk subjects.