During palatogenesis, the palatal medial edge epithelium (MEE) forms the medial epithelial seam (MES) on adhesion of the opposing palatal shelves. The MES eventually disappears, leading to mesenchymal confluence of the palate and completion of palatogenesis. Failure of these processes results in cleft palate, one of the most common congenital anomalies in human affecting around one case in 500-2500 live births. The cell fate of MEE has been controversial for more than 20 years. Recent studies suggest that the disappearance of MES is a complex process involving cell death, epithelial-mesenchymal transition (EMT) and epithelial migration. Interestingly, transforming growth factor-β3 (Tgf β3) expression in MEE and the tip epithelium of the nasal septum begins just before palatal shelf reorientation and lasts until MES disruption, and several works including targeted disruption of the gene have indicated that the process appears to be regulated mainly by the TGFβ3-TGFβR signaling. However, how MEE cells choose their fate and how the cell fate is altered in response to cellular environment remains to be elucidated. 相似文献
α1‐adrenoceptors (α1‐ARs) stimulation has been found to enhance excitatory processes in many brain regions. A recent study in our laboratory showed that α1‐ARs stimulation enhances glutamatergic transmission via both pre‐ and post‐synaptic mechanisms in layer V/VI pyramidal cells of the rat medial prefrontal cortex (mPFC). However, a number of pre‐synaptic mechanisms may contribute to α1‐ARs‐induced enhancement of glutamate release. In this study, we blocked the possible post‐synaptic action mediated by α1‐ARs to investigate how α1‐ARs activation regulates pre‐synaptic glutamate release in layer V/VI pyramidal neurons of mPFC. We found that the α1‐ARs agonist phenylephrine (Phe) induced a significant enhancement of glutamatergic transmission. The Phe‐induced potentiation was mediated by enhancing pre‐synaptic glutamate release probability and increasing the number of release vesicles via a protein kinase C‐dependent pathway. The mechanisms of Phe‐induced potentiation included interaction with both glutamate release machinery and N‐type Ca2+ channels, probably via a pre‐synaptic Gq/phospholipase C/protein kinase C pathway. Our results may provide a cellular and molecular mechanism that helps explain α1‐ARs‐mediated influence on PFC cognitive functions.
The impulse background activity (BA) of neurons of the rat medial vestibular nucleus (MVN) was subjected to computer analysis, and its modifications related to long-term vibration were studied. It was shown that following 5 days of 2-h-long vibration sessions, statistically significant changes in some basic characteristics of BA generated by MVN neurons were observed. More than a twofold increase in the mean BA frequency and substantial shifts practically of all statistical BA parameters were found after 10 days of vibration. Following a 15-day-long vibration, MVN neurons showed a clear-cut tendency to restore control values of the BA indices, which probably was related to adaptation processes. 相似文献
按常规方法将豚鼠固定于立体定位仪架上,用插电极、通电烧灼及亚铁氰化钾甲醛溶液灌流固定的检查技术确定内膝体中心的座标值。结果表明,300—800g动物的内膝体前后座标值 A 及左右座标值 LR 有线性地随体重而增大的趋势,水平座标 H 值则变化较小。三组数据的线性方程为 A=0.0047W 3.9,LL或RL=0.0018W 3.7,H=-3.1。体重400—600g豚鼠的模座标值为 A=6.3,LL 或 RL=4.6,H=-3.1。当从电极引出的短声诱发电位主波为负相时通常提示记录点在该核团内,这可作为进行活体实验时有用的定位辅助指标。 相似文献
Cultural influences on the concept of self is a very important topic for social cognitive neuroscientific exploration, as
yet, little if anything is known about this topic at the neural level. The present study investigates this problem by looking
at the Chinese culture's influence on the concept of self, in which the self includes mother. In Western cultures, self-referential
processing leads to a memory performance advantage over other forms of semantic processing including mother-referential, other-referential
and general semantic processing, and an advantage that is potentially localizable to the medial prefrontal cortex (MPFC).
In Chinese culture, however, the behavioral study showed that mother-referential processing was comparable with self-referential
processing in both memory performance and autonoetic awareness. The present study attempts to address whether similar neural
correlates (e.g. MPFC) are acting to facilitate both types of referencing. Participants judged trait adjectives under three
reference conditions of self, other and semantic processing in Experiment I, and a mother-reference condition replaced the
other-reference condition in Experiment II. The results showed that when compared to other, self-referential processing yielded
activations of MPFC and cingulate areas. However, when compared to mother, the activation of MPFC disappeared in self-referential
processing, which suggests that mother and self may have a common brain region in the MPFC and that the Chinese idea of self
includes mother. 相似文献
Bilateral injection of 6-hydroxydopamine into the medial forebrain bundle (MFB) significantly decreased monoamine concentrations in the hypothalamus. The noradrenaline and serotonin content of the paraventricular nucleus (PVN) was also significantly reduced. These drastic decreases in neurotransmitter concentration did not alter basal secretion of corticosterone. Isoproterenol. a -adrenoceptor agonist (1 mg/kg, i.p.), significantly stimulated corticosterone release in saline and MFB lesioned rats. This stimulation did not differ significantly between the two groups. Clonidine, an 2-adreceptor agonist, injected either intraperitoneally or intracerebrally just dorsal to the PVN, caused a dose-dependent increase in corticosterone secretion. The stimulation of corticosterone release by clonidine (250 g/kg, i.p.) was antagonised by the selective 2-adreceptors antagonist, yohimbine (1 mg/kg, i.p.) and significantly reduced by the MFB lesion. These results suggest that corticosterone secretion is stimulated by activation of 2-adreceptors which occur on noradrenergic nerve terminals in the PVN. 相似文献
Manual tracking of muscle fascicle length changes from ultrasound images is a subjective and time-consuming process. The purpose of this study was to assess the repeatability and accuracy of an automated algorithm for tracking fascicle length changes in the medial gastrocnemius (MG) muscle during passive length changes and active contractions (isometric, concentric and eccentric) performed on a dynamometer. The freely available, automated tracking algorithm was based on the Lucas–Kanade optical flow algorithm with an affine optic flow extension, which accounts for image translation, dilation, rotation and shear between consecutive frames of an image sequence. Automated tracking was performed by three experienced assessors, and within- and between-examiner repeatability was computed using the coefficient of multiple determination (CMD). Fascicle tracking data were also compared with manual digitisation of the same image sequences, and the level of agreement between the two methods was calculated using the coefficient of multiple correlation (CMC). The CMDs across all test conditions ranged from 0.50 to 0.93 and were all above 0.98 when recomputed after the systematic error due to the estimate of the initial fascicle length on the first ultrasound frame was removed from the individual fascicle length waveforms. The automated and manual tracking approaches produced similar fascicle length waveforms, with an overall CMC of 0.88, which improved to 0.94 when the initial length offset was removed. Overall results indicate that the automated fascicle tracking algorithm was a repeatable, accurate and time-efficient method for estimating fascicle length changes of the MG muscle in controlled passive and active conditions. 相似文献
Abstract: Using video-enhanced microscopy and a pulse-radiolabeling paradigm, we show that proteins synthesized in the medial giant axon cell body of the crayfish ( Procambarus clarkii ) are delivered to the axon via fast (∼62 mm/day) and slow (∼0.8 mm/day) transport components. These data confirm that the medial giant axon cell body provides protein to the axon in a manner similar to that reported for mammalian axons. Unlike mammalian axons, the distal (anucleate) portion of a medial giant axon remains intact and functional for >7 months after severance. This axonal viability persists long after fast transport has ceased and after the slow wave front of radiolabeled protein has reached the terminals. These data are consistent with the hypothesis that another source (i.e., local glial cells) provides a significant amount of protein to supplement that delivered to the medial giant axon by its cell body. 相似文献