Neuroscience
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Despite the beneficial effects of cell-based therapies on brain repair shown in most studies, there has not been a consensus regarding the optimal dose of human umbilical cord blood cells (HUCBC) for neonatal hypoxia-ischemia (HI). In this study, we compared the long-term effects of intravenous administration of HUCBC at three different doses on spatial memory and brain morphological changes after HI in newborn Wistar rats. In addition, we tested whether the transplanted HUCBC migrate to the injured brain after transplantation. ⋯ Furthermore, the brain atrophy was also significantly lower in the HI+medium- and high-dose groups compared with the HI+vehicle animals (P<0.01; 0.001, respectively). In addition, HUCBC were demonstrated to be localized in host brains by immunohistochemistry and PCR analyses 7 days after intravenous administration. These results revealed that HUCBC transplantation has the dose-dependent potential to promote robust tissue repair and stable cognitive improvement after HI brain injury.
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Eugenol, which is contained in several plants including clove, has been widely used as an analgesic and anti-inflammatory drug in the dental clinic. Eugenol also has anesthetic effects and produces sedation and the reduction of convulsion threshold. These benefits have been partly attributed to the effects of eugenol on neural tissues, such as inhibition of voltage-gated ion channels. ⋯ On the other hand, the eugenol-induced outward current was not affected by these TRP antagonists. It is concluded that eugenol activates TRPA1 channels in the SG, leading to an increase in the spontaneous release of L-glutamate to SG neurons, and that eugenol also produces a membrane hyperpolarization that is not mediated by TRP channels. Eugenol is suggested to activate different types of TRP channel between the PNS and CNS.
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Omnipause neurons (OPNs) represent a crucial component for the generation of saccadic eye movements. They inhibit saccadic premotor neurons in the paramedian pontine reticular formation (PPRF) as well as in the rostral interstitial nucleus of the medial longitudinal fascicle (RIMLF) during the intersaccadic interval. In turn, inhibition of OPNs is a prerequisite in order to generate saccadic eye movements. ⋯ Combined immunohistochemical staining for various markers revealed in these neurons the expression of parvalbumin, chondroitin sulfate proteoglycan, and glycine, but a lack of serotonin. The results of our study demonstrate the striking similarity between individual elements of the premotor saccadic network in rats and primates. The exact knowledge of their location in rats provides a basis for in vitro studies of the OPNs in rat brainstem slices.
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The nucleus of the solitary tract (NTS), an integral vasomotor region located in the hindbrain, is important for cardiovascular homeostasis. Fractalkine (FKN) and its cognate receptor, CX3CR1, are constitutively expressed in the normal rat brain. The physiological significance of this cytokine and its receptor are not well established. ⋯ When FKN was unilaterally microinjected directly into the commissural and sub-postremal, but not rostral, NTS, blood pressure and heart rate were significantly decreased when compared with saline controls. The FKN-induced depressor and bradycardic responses were inhibited by pretreatment with a phosphoinositide 3-kinase inhibitor, LY294002. These data suggest that the cytokine, FKN, and its receptor, CX3CR1, may modulate cardiovascular responses in the NTS of normal healthy rats via the phosphoinositide 3-kinase intracellular signaling pathway.
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Experiences during critical periods, such as the neonatal and adolescence, play a critical role in determining adult stress-coping behavior. Based on the aforementioned we developed an experimental protocol, which included a neonatal experience and a social stress during adolescence. The serotonergic system is known as an important modulator of coping ability and, in general, emotional balance in both normal and pathological states, such as depression and anxiety, for which females are more vulnerable. ⋯ Corticosterone levels following the FST fell faster in the DER animals. Adolescent stress affected the responses to the adult FSS only in the DER animals, which had decreased 5-HT in the AMY and increased immobility time on both days of the FST, compared with the DER, not stressed in adolescence. The phenotype of the DER animals is in line with the "match-mismatch" hypothesis, which states that if two events during critical periods of life "match" in being mildly stressful, their interaction can be adaptive.