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1.
Diffuse noxious inhibitory controls (DNIC) are a mechanism of endogenous descending pain modulation and are deficient in a large proportion of chronic pain patients. However, the pathways involved remain only partially determined with several cortical and brainstem structures implicated. This study examined the role of the dorsal reticular nucleus (DRt) and infralimbic (ILC) region of the medial prefrontal cortex in DNIC. In vivo electrophysiology was performed to record from dorsal horn lamina V/VI wide dynamic range neurones with left hind paw receptive fields in anaesthetised sham‐operated and L5/L6 spinal nerve‐ligated (SNL) rats. Evoked neuronal responses were quantified in the presence and absence of a conditioning stimulus (left ear clamp). In sham rats, DNIC were reproducibly recruited by a heterotopically applied conditioning stimulus, an effect that was absent in neuropathic rats. Intra‐DRt naloxone had no effect on spinal neuronal responses to dynamic brush, punctate mechanical, evaporative cooling and heat stimuli in sham and SNL rats. In addition, intra‐DRt naloxone blocked DNIC in sham rats, but had no effect in SNL rats. Intra‐ILC lidocaine had no effect on spinal neuronal responses to dynamic brush, punctate mechanical, evaporative cooling and heat stimuli in sham and SNL rats. However, differential effects were observed in relation to the expression of DNIC; intra‐ILC lidocaine blocked activation of DNIC in sham rats but restored DNIC in SNL rats. These data suggest that the ILC is not directly involved in mediating DNIC but can modulate its activation and that DRt involvement in DNIC requires opioidergic signalling. 相似文献
2.
Adeline Gazan Daniel Rial Serge N. Schiffmann 《The European journal of neuroscience》2020,51(6):1388-1402
The striatum is mainly composed by medium spiny neurons (95 %) (MSNs). Although outnumbered, in other brain regions such as the hippocampus and the cortex, somatostatin interneurons (SSTi) are known to control and fine‐tune the activity of principal cells. This information is still fragmented for the striatum. Here, we questioned the striatal functional consequences of the selective ablation of SSTi in the striatum at the behavioural and cellular levels. We identified increased excitability coupled with decreased distal spine density in MSNs from SSTi‐ablated mice. Although the ethological behavioural analysis did not reveal differences between the groups, SSTi‐ablated mice were significantly more sensitive to the locomotor effects of cocaine without changes in motivation. This was accompanied by increased expression of the dopamine transporter (DAT) in the ventral striatum. Altogether, we show that SSTi are important players in the maintenance of MSN excitability and spine density impacting on mechanisms towards hyperdopaminergic states. 相似文献
3.
Zebra finches (Taeniopygia guttata) use their voices for communication. Song structures in the songs of individual males are important for sound recognition in females. The caudomedial mesopallium (CMM) and nidopallium (NCM) are known to be essential higher auditory regions for sound recognition. These two regions have also been discussed with respect to their fundamental functions and song selectivity. To clarify their functions and selectivity, we investigated latencies and spiking patterns and also developed a novel correlation analysis to evaluate the relationship between neural activity and the characteristics of acoustic factors. We found that the latencies and spiking patterns in response to song stimuli differed between the CMM and NCM. In addition, our correlation analysis revealed that amplitude and frequency structures were important temporal acoustic factors for both regions. Although the CMM and NCM have different fundamental functions, they share similar encoding systems for acoustic factors. 相似文献
4.
Phoenixin (PNX) is a neuropeptide shown to play roles in the control of reproduction. The nucleus of the solitary tract (NTS), a critical autonomic integrating centre in the hindbrain, is one of many areas with dense expression of PNX. Using coronal NTS slices obtained from male Sprague‐Dawley rats, the present study characterised the effects of PNX on both spike frequency and membrane potential of NTS neurones. Extracellular recordings demonstrated that bath‐applied 10 nmol L‐1 PNX increased the firing frequency in 32% of NTS neurones, effects which were confirmed with patch‐clamp recordings showing that 50% of NTS neurones tested depolarised in response to application of the peptide. Surprisingly, the responsiveness to PNX in NTS neurones then declined suddenly to 9% (P < 0.001). This effect was subsequently attributed to stress associated with construction in our animal care facility because PNX responsiveness was again observed in slices from rats delivered and maintained in a construction‐free facility. We then examined whether this loss of PNX responsiveness could be replicated in rats placed on a chronic stress regimen involving ongoing corticosterone (CORT) treatment in the construction‐free facility. Slices from animals treated in this way showed a similar lack of neuronal responsiveness to PNX (9.1 ± 3.9%) within 2 weeks of CORT treatment. These effects were specific to PNX responsiveness because CORT treatment had no effect on the responsiveness of NTS neurones to angiotensin II. These results are the first to implicate PNX with respect to directly controlling the excitability of NTS neurones and also provide intriguing data showing the plasticity of these effects associated with environmental and glucocorticoid stress levels of the animal. 相似文献
5.
In mammals, the central pacemaker that coordinates 24‐hr rhythms is located in the suprachiasmatic nucleus (SCN). Individual neurons of the SCN have a molecular basis for rhythm generation and hence, they function as cell autonomous oscillators. Communication and synchronization among these neurons are crucial for obtaining a coherent rhythm at the population level, that can serve as a pace making signal for brain and body. Hence, the ability of single SCN neurons to produce circadian rhythms is equally important as the ability of these neurons to synchronize one another, to obtain a bona fide pacemaker at the SCN tissue level. In this chapter we will discuss the mechanisms underlying synchronization, and plasticity herein, which allows adaptation to changes in day length. Furthermore, we will discuss deterioration in synchronization among SCN neurons in aging, and gain in synchronization by voluntary physical activity or exercise. 相似文献
6.
Jaime A. Willett Jinyan Cao Ashlyn Johnson Opal H. Patel David M. Dorris John Meitzen 《The European journal of neuroscience》2020,52(1):2737-2755
The neuroendocrine environment in which the brain operates is both dynamic and differs by sex. How differences in neuroendocrine state affect neuron properties has been significantly neglected in neuroscience research. Behavioral data across humans and rodents indicate that natural cyclical changes in steroid sex hormone production affect sensorimotor and cognitive behaviors in both normal and pathological contexts. These behaviors are critically mediated by the caudate–putamen. In the caudate–putamen, medium spiny neurons (MSNs) are the predominant and primary output neurons. MSNs express membrane‐associated estrogen receptors and demonstrate estrogen sensitivity. However, how the cyclical hormone changes across the estrous cycle may modulate caudate–putamen MSN electrophysiological properties remains unknown. Here, we performed whole‐cell patch‐clamp recordings on male, diestrus female, proestrus female, and estrus female caudate–putamen MSNs. Action potential, passive membrane, and miniature excitatory post‐synaptic current properties were assessed. Numerous MSN electrical properties robustly differed by cycle state, including resting membrane potential, rheobase, action potential threshold, maximum evoked action potential firing rate, and inward rectification. Strikingly, when considered independent of estrous cycle phase, all but one of these properties do not significantly differ from male MSNs. These data indicate that female caudate–putamen MSNs are sensitive to the estrous cycle, and more broadly, the importance of considering neuroendocrine state in studies of neuron physiology. 相似文献
7.
目的研究养心定悸胶囊联合小剂量美托洛尔治疗频发室性早搏患者的临床疗效及对心脏电生理指标的影响。方法选取2017年3月—2018年3月在沈阳医学院附属中心医院心内科诊治的频发室性早搏患者80例,随机分为2组,每组各有40例。所有患者给予基础疾病治疗,对照组加服酒石酸美托洛尔片25 mg/次,2次/d。观察组在此基础上加服养心定悸胶囊6粒/次,2次/d。连续治疗6周后对比2组患者临床疗效、24 h平均心率及心脏电生理指标。结果治疗后对照组中医证候疗效总有效率为67.5%(27/40),观察组为87.5%(35/40),组间比较差异有统计学意义(P<0.05)。治疗后2组患者24 h平均心率、白天平均心率及夜间平均心率与治疗前比较均有所下降,但是组内与组间比较差异均无统计学意义(P均>0.05)。治疗后观察组Tp-e间期、QTcd与对照组比较缩短更为明显(P均<0.05)。结论养心定悸胶囊治疗频发室性早搏时不降低患者平均心率,可缩短患者Tp-e间期及QTcd,临床疗效更好。 相似文献
8.
Xiaokuang Ma Ke Chen Yuehua Cui Guanqun Huang Antoine Nehme Le Zhang Handong Li Jing Wei Katerina Liong Qiang Liu Lingling Shi Jie Wu Shenfeng Qiu 《Journal of neuroscience research》2020,98(10):1968-1986
Microglia populate the early developing brain and mediate pruning of the central synapses. Yet, little is known on their functional significance in shaping the developing cortical circuits. We hypothesize that the developing cortical circuits require microglia for proper circuit maturation and connectivity, and as such, ablation of microglia during the cortical critical period may result in a long-lasting circuit abnormality. We administered PLX3397, a colony-stimulating factor 1 receptor inhibitor, to mice starting at postnatal day 14 and through P28, which depletes >75% of microglia in the visual cortex (VC). This treatment largely covers the critical period (P19-32) of VC maturation and plasticity. Patch clamp recording in VC layer 2/3 (L2/3) and L5 neurons revealed increased mEPSC frequency and reduced amplitude, and decreased AMPA/NMDA current ratio, indicative of altered synapse maturation. Increased spine density was observed in these neurons, potentially reflecting impaired synapse pruning. In addition, VC intracortical circuit functional connectivity, assessed by laser scanning photostimulation combined with glutamate uncaging, was dramatically altered. Using two photon longitudinal dendritic spine imaging, we confirmed that spine elimination/pruning was diminished during VC critical period when microglia were depleted. Reduced spine pruning thus may account for increased spine density and disrupted connectivity of VC circuits. Lastly, using single-unit recording combined with monocular deprivation, we found that ocular dominance plasticity in the VC was obliterated during the critical period as a result of microglia depletion. These data establish a critical role of microglia in developmental cortical synapse pruning, maturation, functional connectivity, and critical period plasticity. 相似文献
9.
10.
声带运动障碍的病因和临床表现复杂多变,涉及多学科,从病因上分为神经源性和非神经源性。对于神经源性声带运动障碍的诊治,首先通过喉镜等检查明确有无声带运动障碍及严重程度,值得注意的是声带纵向张力变化障碍也属于运动障碍的范畴;然后采用喉肌电图(LEMG)检查进行定性分析,在确诊神经源性损伤后,进一步对神经损伤部位进行定位诊断并查找导致神经损伤的病因;同时根据喉部神经电生理评估结果,判断预后。最后综合上述的评估结果制定相应的治疗策略。 相似文献