Distribution of calbindin D-28K and parvalbumin immunoreactivities in the nucleus olfactorius anterior of the rat

The distributions of calbindin D-28K (CaBP) and parvalbumin (PV) in the rat nucleus olfactorius anterior (NOA) were described using monoclonal antibodies and the avidin-biotin-peroxidase method. The NOA showed a high immunoreactivity for CaBP, with a rostrocaudal increase in the positive neurons and fibres. Pars externa (NOAe) was the only subdivision which showed a low CaBP immunostaining. PV-positive elements were less abundant than those CaBP immunostained. The main difference in the distributions for both proteins was observed in the pars medialis which was practically PV negative. PV- and CaBP-stained neurons showed similar morphologies in the subdivisions where they were present. In NOAe, we observed a characteristic PV- and CaBP-positive neuronal type, with an oriented dendritic pattern. Transition areas were clearly observable in both CaBP- and PV-labelled sections.     

Modulation of vertebrate neuronal calcium channels by transmitters

A large number of neurotransmitters have now been shown to reduce the amplitude and slow the activation kinetics of whole cell HVA I_Ca in a great diversity of neurons. These transmitters include l-glutamate (AMPA/kainate, metabotropic and NMDA receptors), G AB A (via GABA_B receptors, NA (via α₂ receptors), 5-HT, N A (via α₂ receptors), DA and several peptides. Both whole-cell and single-channel studies have demonstrated that the N-channel is the most common channel type to be blocked by transmitters, although an inhibition of the L-type channel has also occasionally been reported. The suppression of the N-type Ca current was commonly shown to be voltage-dependent, with a relief at large positive voltages. Strong evidence has been put forward showing that the transmitter action is mediated by a G-protein, with GDP-β-S blocking transmitter action, and GTP-γ-S directly inhibiting the Ca channel. Moreover, pertussis toxin blocked the transmitter action in most neurons, and following such block, injection of the G-protein G₀ restored transmitter action. A direct link between the G-protein and the Ca channel has been widely theorized to mediate the action of transmitters on certain neurons. There is also some evidence that certain transmitters in specific neurons mediate calcium channel inhibition through a 2nd messenger, perhaps protein kinase C.Transmitters have also been found, although uncommonly, to inhibit HVA L-type and LVA T-type channels. In addition, an enhancement of both HVA and LVA, Ca currents by transmitters has been demonstrated, and substantial evidence exists for mediation of this action by cAMP.     

磷脂酶A2激活在鼠急性缺血性脑损伤中的作用机制

目的 探讨急性脑缺血后脑组织内磷脂酶A2（PLA2）激活及细胞内[Ca^2 ]i与脑损伤的关系，为预防和治疗急性缺血性脑损伤提供理论基础和新的思路。方法 将局灶性脑缺血模型大鼠分5组（假手术组、缺血30、60、90、120min组），测定脑组织PLA2活力、脑细胞[Ca^2 ]i、脑含水量及缺血120min组脑组织PLA2表达量的改变。结果 脑缺血120min脑组织PLA2活性、[Ca^2 ]i、脑含水量较假手术组明显升高，并与时间呈正相关，缺血120min后脑组织中出现sPLA2-ⅡAmRNA表达，且cPLA2-ⅣmRNA表达水平较假手术组明显增强。结论 磷脂酶A2激活参与了脑缺血后神经细胞内钙超载及脑损伤的整人病理过程。     

Calcium incorporation in cultured chondroblasts perturbed by an electromagnetic field

We tested the hypothesis that electric perturbation influences 45Ca incorporation in extracellular matrix (ECM) of cartilage in vitro. Hypertrophic chondroblasts of tibial epiphyses (HC), sternum (SC), and skin fibroblasts (F) were cultured from chick embryos. HC, SC, and F cells were micromass seeded three times per week and maintained at 37.5 degrees C with 5% CO2 for two weeks. Cultures were randomly designated control (C) or exposed (E) to a pulsed electromagnetic field (PEMF). A time course experiment of calcium incorporation for all cultured groups showed that 24 h of exposure produced the largest biological response in chondroblasts. Calcium incorporation required supplemental phosphate. Autoradiography data indicated that the calcium incorporation into macromolecules largely occurred in the ECM. 45Ca steady-state perturbation was enhanced by Streptomyces hyaluronidase (SH) but not by testicular hyaluronidase (TH). 45Ca incorporation experiments tested the effects of phosphate, SH, TH, and PEMF alone and in various combinations on these cultures. Only PEMF or SH plus PEMF with phosphate enhanced 45Ca incorporation. Other experiments examined the effect of rotenone or freeze-thawing on cells exposed to PEMF. PEMF plus freeze-thaw enhanced calcium incorporation in HC only. PEMF appeared to cause disruption of the ECM, enhancing the probability of matrix calcification.     

维生素D_3与心肌细胞电活动关系的实验研究

本实验利用标准玻璃微电极技术和微机系统的实时应用,在离体豚鼠右心室乳头肌上观察维生素D_3对其细胞电活动的影响。结果表明维生素D_3可使心肌细胞动作电位和零相最大去极化速率发生明显改变,其变化主要是由于通过细胞膜慢通道有大量的Ca~(2+)内流,使细胞内Ca~(2+)超负荷来实现的。     

钙剂加维生素D治疗对糖尿病患者钙代谢的影响

本文报道NIDDM患者在常规治疗的基础上加用钙剂和维生素D治疗后的钙代谢变化。糖尿病患者单纯用常规治疗控制血糖后,负钙平衡不能完全纠正,而加用钙剂和维生素D治疗后,负钙平衡能完全纠正,并且高于正常对照组平衡值(P<0.01)。说明钙剂加维生素D治疗对糖尿病性骨质疏松是有益的。     

Parvalbumin expression reveals a vibrissa-related pattern in rabbit SI cortex

The expression of parvalbumin-like immunoreactivity (PV-LIR) was examined in the mystacial representation within the primary somatosensory cortex (SI) of postnatal day 21 and adult rabbits. PV-LIR was expressed in a prominent vibrissa-like array of patches in layer IV despite the fact that barrels were indistinct in the cytoarchitecture. Each patch consisted of dense terminal-like PV-LIR and a preferential concentration of intensely labeled stellate neurons. Layer V contained scattered small and large intensely labeled basket cells. Layer Vb had a distinct layer of lightly labeled large pyramidal cells that received labeled basket cell terminations. Upper layer VI also contained patches of terminal-like PV-LIR that were in register with the overlying vibrissae pattern. These patches also contained a preferential distribution of labeled non-pyramidal cells as well as modified pyramidal cells. These results suggest that PV-LIR in rabbits delineates cortical modules composed of thalamorcotical afferents and inhibitory local circuits in the absence of a distinct barrel cytoarchitecure. In contrast, prior studies of rat SI cortex have revealed a distinct barrel cytoarchitecture but a uniform distribution of PV-LIR. The differences in PV-LIR between rodents and lagomorphs within the vibrissae representation in SI may be related to species differences in thalamic and local cortical circuits devoted to the whisker sense.     

异搏定区域动脉灌注在阻止急性胰腺炎重症化治疗中的作用

目的探讨钙拮抗剂异搏定区域动脉灌注在阻止急性胰腺炎重症化治疗中的作用。方法45例轻型急性胰腺炎患者被随机分为3组常规治疗组、静脉治疗组及动脉灌注组。入院后,常规治疗组采取常规保守治疗;静脉治疗组行合理液体治疗,静脉注射异搏定;动脉灌注组液体补充同时采用持续动脉灌注异搏定1~2周。测定治疗后1、4及7d血清肿瘤坏死因子-α(TNF-α)、白介素-1β(IL-1β)、黏附分子-1(ICAM-1)及P-选择素(P-selectin)水平。结果治疗后4、7d,血清TNF-α和P-selectin水平动脉灌注组较静脉治疗组及常规治疗组明显降低(P<0.05);血清IL-1β水平动脉灌注组和静脉治疗组均较常规治疗组明显降低(P<0.05);血清ICAM-1水平动脉灌注组明显低于常规治疗组(P<0.05)。结论持续区域动脉灌注异搏定可能通过减少细胞因子的产生,抑制黏附分子P-selectin和ICAM-1的上调,阻止急性胰腺炎重症化发展。     

氯胺酮对荷包牡丹碱诱导PC12细胞内Ca2+浓度波动方式的影响

目的研究氯胺酮对荷包牡丹碱诱导PCI2细胞内Ca^2＋浓度波动方式的影响。方法使用含25ng／LNGF的DMED培养基在多聚赖氨酸包被的培养皿中培养PCl2细胞；与终浓度10gmol／L的Ca^2＋指示剂Fluo-3 AM ester共孵育30min洗涤后，加入终浓度50gmol／L荷包牡丹碱；在激光共聚焦显微镜选定多个细胞分别测定荧光强度的变化；随后加入氯胺酮，记录细胞荧光强度的改变。在试验结束前依次加入Triton X-100和EGTA分别记录单个细胞最大荧光强度（Fmax）和最小荧光强度（Fmin），以计算细胞内Ca^2＋的相对强度。结果氯胺酮不改变荷包牡丹碱诱导PCl2细胞内Ca^2＋浓度波动的基线，但抑制细胞内Ca^2＋浓度升高的幅度（P〈0．05），缩短相邻波峰间的时间间隙（P〈0．05）。结论氯胺酮不仅改变荷包牡丹碱诱导PCl2细胞内Ca^2＋浓度升高的幅度，而且改变Ca^2＋浓度波动的周期。