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Postnatal development of hippocampal dentate granule cell γ-aminobutyric acid_A receptor pharmacological properties

MOLECULAR PHARMACOLOGY 1999年第3期55卷 444-452页

作者： Kapur, J Macdonald, RL Univ Michigan Med Ctr Dept Neurol Ann Arbor MI 48109 USA Univ Michigan Med Ctr Dept Physiol Ann Arbor MI 48109 USA

Postnatal development of hippocampal dentate granule cell gamma-aminobutyric acid(A) (GABA(A)) receptor pharmacological properties was studied. Granule cells were acutely isolated from hippocampi of 7- to 14- and 45- to 52-day-old rats, and whole cell patch-clamp recordings were obtained. The sensitivity of GABA(A) receptors to GABA and modulation of GABA(A) receptor currents by benzodiazepines (BZ), zinc, furosemide, and loreclezole was studied. Multiple changes in the pharmacological properties of dentate granule-cell GABA(A) receptors occurred during the first 52 days of postnatal development: GABA-evoked maximal current increased with postnatal age;GABA(A) receptors changed from BZ type 3 in young rats to BZ type 1 in adult rats;furosemide and zinc inhibited GABA, receptor currents in young rats but not in adult rats;the fraction of cells that expressed loreclezole-sensitive GABA(A) receptors increased with postnatal age. These findings suggest that dentate granule cells in young and adult animals express pharmacologically distinct GABA(A) receptors and that the postnatal development of these receptors is prolonged, lasting at least 45 days. Comparison with the previously reported pharmacological properties of GABA(A) receptors on dentate granule cells acutely isolated from hippocampi of 28- to 35-day-old rats suggests that receptors expressed at that age have properties intermediate between young and adult rats.

关键词：苯二氮|艹卓|类/药理学齿状回/细胞学齿状回/生长和发育齿状回/代谢电生理学呋塞米/药理学受体 GABA-A/药物作用受体 GABA-A/代谢三唑类/药理学锌/药理学动物大鼠

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Single channel properties of P2X ATP receptors in outside-out patches from rat hippocampal granule cells

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JOURNAL OF PHYSIOLOGY-LONDON 2000年第3期527卷 529-547页

作者： Wong, AYC Burnstock, G Gibb, AJ UCL Dept Pharmacol London WC1E 6BT England UCL Auton Neurosci Inst London WC1E 6BT England

1. The single channel properties of P2X ATP receptors were investigated in outside-out patches from hippocampal granule cells in brain slices from 12-day-old rats. The results demonstrate that functional P2X ATP receptors are expressed in hippocampal granule cells and, combined with previously published information on the P2X subunits expressed in the hippocampus, suggest that the receptors may be heteromers of the P2X(4) and P2X(6) subunits or P2X(1), P2X(2), P2X(4) and P2X(6) subunits. 2. Two distinct types of P2X channel openings were observed. A flickery P2X receptor channel was observed in three patches with a mean chord conductance of 32 +/- 6 pS, a mean open time of 1.0 +/- 0.3 ms and a mean burst length of 11 +/- 5 ms at a membrane potential of -60 mV. A large conductance P2X receptor was observed in 19 out of 98 patches with a mean conductance of 56 +/- 1.8 pS, a linear current-voltage relationship between -80 and +60 mV with a reversal potential around 0 mV, a mean open time of 2.6 +/- 0.2 ms and a mean burst length of 8.8 + 1.8 ms at -60 mV. At an ATP concentration of 1 mM, these channels exhibited a low steady-state open probability (P-open, 0.07 +/- 0.008;n=15), little apparent desensitisation and were also activated by alpha,beta-methylene ATP (alpha,beta-meATP, 40 mu M;P-open, 0.007 +/- 0.0002;conductance, 57 +/- 1.1 pS;n = 3). No decrease in the single channel conductance was observed on increasing the free extracellular calcium concentration from 0.3 to 0.85 mM. 3. Channel closed time distributions were fitted with five exponential components with time constants land relative areas) of 90 mu s (20%), 0.77 ms (32%), 10 ms (15%), 90 ms (18%) and 403 ms (15%) at 1 mM ATP. Of these, the first two components are suggested to represent galls within single activations of the receptor based on the lack of agonist concentration dependence of these two shut time components between 1 mu M and 1 mM ATP. 4. Suramin (40 mu M) significantly increased the single ch

关键词：腺苷三磷酸/类似物和衍生物腺苷三磷酸/药理学钙/代谢细胞质颗粒/代谢齿状回/细胞学齿状回/药物作用齿状回/代谢电生理学海马/细胞学海马/药物作用海马/代谢离子通道闸门/生理学离子通道/代谢膜电位/生理学膜片钳术大鼠 Sprague-Dawley 受体嘌呤能P2/代谢舒拉明/药理学动物男(雄)性大鼠

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Loss of BETA2/NeuroD leads to malformation of the dentate gyrus and epilepsy

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PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA 2000年第2期97卷 865-870页

作者： Liu, M Pleasure, SJ Collins, AE Noebels, JL Naya, FJ Tsai, MJ Lowenstein, DH Baylor Coll Med Dept Cell Biol Houston TX 77030 USA Baylor Coll Med Dept Neurol Houston TX 77030 USA Univ Calif San Francisco Epilepsy Res Lab Dept Neurol San Francisco CA 94143 USA

BETA2/NeuroD is a homologue of the Drosophila atonal gene that is widely expressed during development in the mammalian brain and pancreas. Although studies in Xenopus suggest that BETA2/NeuroD is involved in cellular differentiation, its function in the mammalian nervous system is unclear. Here we show that mutant mice homozygous for a deletion at the BETA2/NeuroD locus fail to develop a granule cell layer within the dentate gyrus, one of the principal structures of the hippocampal formation. To understand the basis of this abnormality, we analyzed dentate gyrus development by using immunocytochemical markers in BETA2/NeuroD-deficient mice. The early cell populations in the dentate gyrus, including Cajal-Retzius cells and radial glia, are present and appear normally organized. The migration of dentate precursor cells and newly born granule cells from the neuroepithelium to the dentate gyrus remains intact. However, there is a dramatic defect in the proliferation of precursor cells once they reach the dentate and a significant delay in the differentiation of granule cells. This leads to malformation of the dentate granule cell layer and excess cell death. BETA2/NeuroD null mice also exhibit spontaneous limbic: seizures associated with electrophysiological evidence of seizure activity in the hippocampus and cortex. These findings thus establish a critical role of BETA2/NeuroD in the development of a specific class of neurons. Furthermore, failure to express BETA2/NeuroD leads to a stereotyped pattern of pathological excitability of the adult central nervous system.

关键词：碱性螺旋-环-螺旋转录因子类细胞分化细胞分裂 DNA结合蛋白质类/遗传学齿状回/胚胎学齿状回/代谢齿状回/病理学癫痫/遗传学基因表达调控发育期基因型海马/细胞学海马/胚胎学海马/代谢原位杂交边缘系统/代谢边缘系统/病理生理学小鼠近交C57BL 小鼠近交系小鼠突变型突变神经元/细胞学神经元/代谢表型反式激活因子类/遗传学动物女(雌)性男(雄)性小鼠

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Effect of 7-nitroindazole, a selective neuronal nitric oxide synthase inhibitor, on parvalbumin immunoreactivity after cerebral ischaemia in the hippocampus of the mongolian gerbil

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ANATOMIA HISTOLOGIA EMBRYOLOGIA-JOURNAL OF VETERINARY MEDICINE SERIES C-ZENTRALBLATT FUR VETERINARMEDIZIN REIHE C 1999年第5-6期28卷 325-329页

作者： Kwon, YB Yoon, YS Han, HJ Lee, JH Seoul Natl Univ Coll Vet Med Dept Vet Physiol Suwon South Korea Seoul Natl Univ Coll Vet Med Dept Vet Histol Suwon South Korea Chonnam Natl Univ Coll Vet Med Hormone Res Ctr Kwangju South Korea

Previous studies have demonstrated that a loss of parvalbumin-immunoreactive (PV-ir) neurones is observed in the hippocampus after transient cerebral ischaemia. However, whether the loss of parvalbumin (PV) immunoreactivity is related to the over-production of nitric oxide (NO) during cerebral ischaemia has not been evaluated. This study was designed to test the effect of 7-nitroindazole pre-treatment (7-NI, 50 mg/kg), a selective neuronal NO synthase inhibitor, on PV immunoreactivity and its cellular activity following forebrain ischaemia. PV-ir neurones in the hippocampus of the control group were widely distributed in the pyramidal cell layer and stratum oriens of CA1 and CA3, and the granular cell layer of dentate gyrus. 7-NI pre-treatment completely suppressed the reduction of PV immunoreactivity in CA1 that was observed in the ischaemia-induced group. Subsequently, 7-NI pre-treatment also protected against the structural loss of microtubule-associated protein 2 (MAP2) immunoreactivity in CA1 after ischaemic insult. In addition, the Fos-defined neuronal activity of PV-ir neurones was slightly increased by the 7-NI pre-treatment 3 h after ischaemia. Based on these data, we conclude that the neuronal toxicity of NO may be involved in the loss of PV-ir neurones after cerebral ischaemia.

关键词：齿状回/药物作用齿状回/代谢酶抑制剂/药理学沙鼠亚科海马/药物作用海马/代谢吲唑类/药理学脑缺血发作短暂性/代谢一氧化氮合酶/拮抗剂和抑制剂小白蛋白/代谢前脑锥体细胞/药物作用锥体细胞/代谢动物男(雄)性

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Zinc and ifenprodil allosterically inhibit two separate polyamine-sensitive sites at N-methyl-D-aspartate receptor complex

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JOURNAL OF PHARMACOLOGY AND EXPERIMENTAL THERAPEUTICS 1999年第3期289卷 1584-1591页

作者： Berger, ML Rebernik, P Univ Vienna Inst Biochem Pharmacol A-1090 Vienna Austria

In this study, we investigated the hypothesis that inhibition of the N-methyl-D-aspartate (NMDA) receptor complex by zinc involves a polyamine-sensitive regulatory site. We found that the specific binding of the open channel ligand [H-3]MK-801 to rat hippocampal membranes 1) was inhibited by low concentrations of Zn2+ (IC50 = 5.5 mu M) by 65%. 2) This high-affinity component of inhibition was reversed by the polyamine spermine to an extent that could be reconciled with competitive interaction between Zn2+ and spermine. 3) Partial inhibition by Zn2+ was additive with partial inhibition by ifenprodil, an inhibitor of the NMDA receptor complex supposed to act at a polyamine-sensitive regulatory site, and 4) in membranes prepared from several other brain regions, inhibition of [H-3]MK-801 binding by Zn2+ and by ifenprodil was either less than additive, or superadditive. Our observation that ifenprodil, at concentrations saturating its high-affinity component of inhibition, prevented spermine from reversing the inhibition by Zn2+ indicates that spermine did not increase [H-3]MK-801 binding by competition with Zn2+ but rather via another polyamine regulatory site not sensitive to zinc but sensitive to ifenprodil. We conclude that Zn2+ reduces channel opening of the NMDA receptor complex by allosteric inhibition of a polyamine-sensitive regulatory site different from that inhibited by ifenprodil and that these two allosteric sites influence each other in a manner dependent on the brain region investigated. The different proportions of zinc/ifenprodil inhibition in different regions could reflect different percentages of various NMDA receptor subtypes.

关键词：别构调节结合竞争性脑/代谢细胞膜/代谢齿状回/代谢地卓西平马来酸盐/药代动力学兴奋性氨基酸拮抗剂/药理学海马/代谢动力学神经元/代谢器官特异性哌啶类/药理学放射配体测定大鼠 Wistar 受体 N-甲基-D-天冬氨酸/化学受体 N-甲基-D-天冬氨酸/药物作用受体 N-甲基-D-天冬氨酸/代谢精胺/药理学氚锌/药理学动物男(雄)性大鼠

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NMDA-induced ⁴⁵Ca release in the dentate gyrus of newborn rats:: in vivo microdialysis study

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NEUROCHEMISTRY INTERNATIONAL 2000年第2-3期37卷 307-316页

作者： Makarewicz, D Salinska, E Puka-Sundvall, M Alaraj, M Ziembowicz, A Skangiel-Kramska, J Jablonska, B Bona, E Hagberg, H Lazarewicz, JW Polish Acad Sci Med Res Ctr Dept Neurochem PL-02106 Warsaw Poland Univ Gothenburg Dept Anat & Cell Biol Gothenburg Sweden Univ Gothenburg Dept Physiol Gothenburg Sweden Univ Gothenburg Dept Obstet & Gynecol Gothenburg Sweden Polish Acad Sci Dept Neurophysiol Nencki Inst Expt Biol Warsaw Poland

This in vivo study, aimed at detecting the N-methyl-D-aspartate (NMDA) evoked Ca2+-induced Ca2+ release from intracellular stores in the neonatal rat brain, demonstrates that the application of 5 mM N-methyl-D-aspartate via a microdialysis probe for 20 min to the dentate gyrus (DG) of halotane-anesthetized 7 day-old (postnatal day 7, PND 7) rats induces a prolonged decrease in Ca2+ concentration in an initially calcium-free dialysis medium, indicative of a drop in the extracellular concentration of Ca2+ and Ca2+ influx to neurons. In parallel experiments, a huge NMDA-evoked release of Ca-45 from the pre-labeled endogenous Ca2+ pool was observed and interpreted as the expression of intracellular Ca2+ release. Dantrolene (100 mu M) significantly inhibited the NMDA-induced Ca-45 release, whereas 250 mu M ryanodine exerted an unspecific biphasic effect. Autoradiographic and immunocytochemical detection of ryanodine receptors and calbindin D-28K respectively, in the hippocampal region of PND 7 rats displayed a pronounced expression of [H-3]ryanodine binding sites in the DG, but only a slight immunoreactivity of calbindin D-28K. Plastic changes in neurons or excitotoxic neuronal damage induced by the activation of NMDA receptors are mediated by Ca2+ signals, resulting from an influx of extracellular Ca2+, and also in some neurons, from the release of intracellular Ca2+. Our previous in vivo microdialysis experiments visualized NMDA-evoked Ca-45 release in the adult rat dentate gyrus, attributable to Ca2+-induced Ca2+ release from the ryanodine-sensitive pool. An additional role of calbindin in the mechanism of this phenomenon has been suggested. This aspect has not been studied in vivo in newborn rats. Our present results indicate that the release of Ca-45 from the prelabeled intracellular, dantrolene-sensitive Ca2+ pool in the DG neurons of immature rats, most probably representing a phenomenon of Ca2+-induced Ca2+ release, significantly participates in the generation of

关键词：动物新生/代谢放射自显影术钙/代谢钙放射性同位素丹曲林/药理学齿状回/药物作用齿状回/代谢兴奋性氨基酸激动剂/药理学免疫组织化学微透析肌松弛药中枢性/药理学 N-甲基天冬氨酸/药理学大鼠 Wistar 兰尼碱受体钙释放通道/药物作用兰尼碱受体钙释放通道/代谢动物大鼠

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Atm and Bax cooperate in ionizing radiation-induced apoptosis in the central nervous system

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PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA 2000年第2期97卷 889-894页

作者： Chong, MJ Murray, MR Gosink, EC Russell, HRC Srinivasan, A Kapsetaki, M Korsmeyer, SJ McKinnon, PJ St Jude Childrens Res Hosp Dept Genet Memphis TN 38101 USA IDUN Pharmaceut Inc La Jolla CA 92037 USA Harvard Univ Sch Med Dana Farber Canc Inst Dept Pathol & Med Boston MA 02115 USA

Ataxia-telangiectasia is a hereditary multisystemic disease resulting from mutations of ataxia telangiectasia, mutated (ATM) and is characterized by neurodegeneration, cancer, immune defects, and hypersensitivity to ionizing radiation. The molecular details of ATM function in the nervous system are unclear, although the neurological lesion in ataxia-telangiectasia becomes apparent early in life, suggesting a developmental origin. The central nervous system (CNS) of Atm-null mice shows a pronounced defect in apoptosis induced by genetoxic stress, suggesting ATM functions to eliminate neurons with excessive genomic damage. Here, we report that the death effector Bax is required for a large proportion of Atm-dependent apoptosis in the developing CNS after ionizing radiation (IR). Although many of the same regions of the CNS in both Bax-/- and Atm-/- mice were radioresistant, mice nullizygous for both Bax and Atm showed additional reduction in IR-induced apoptosis in the CNS. Therefore, although the major IR-induced apoptotic pathway in the CNS requires Atm and Bax, a p53-dependent collateral pathway exists that has both Atm- and Bax-independent branches. Further, Atm- and Bax-dependent apoptosis in the CNS also required caspase-3 activation. These data implicate Bax and caspase-3 as death effecters in neurodegenerative pathways.

关键词：细胞凋亡/遗传学细胞凋亡/辐射效应印迹法蛋白质半胱氨酸天冬氨酸蛋白酶3 半胱氨酸天冬氨酸蛋白酶/代谢细胞周期蛋白质类中枢神经系统/细胞学中枢神经系统/代谢中枢神经系统/辐射效应小脑/代谢小脑/辐射效应 DNA结合蛋白质类齿状回/代谢齿状回/辐射效应酶激活/辐射效应基因型小鼠基因敲除蛋白质丝氨酸苏氨酸激酶/遗传学蛋白质丝氨酸苏氨酸激酶/代谢蛋白质丝氨酸苏氨酸激酶/生理学原癌基因蛋白质类/遗传学原癌基因蛋白质类/代谢原癌基因蛋白质类/生理学原癌基因蛋白质c-bcl-2 辐射电离视网膜/代谢视网膜/辐射效应肿瘤抑制蛋白质p53/遗传学肿瘤抑制蛋白质p53/代谢肿瘤抑制蛋白质p53/生理学肿瘤抑制蛋白质类 bcl-2相关X蛋白质动物小鼠

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Physiological properties of GABA_A receptors from acutely dissociated rat dentate granule cells

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JOURNAL OF NEUROPHYSIOLOGY 1999年第5期81卷 2464-2471页

作者： Kapur, J Haas, KF MacDonald, RL Univ Michigan Med Ctr Dept Neurol Ann Arbor MI 48104 USA Univ Michigan Med Ctr Dept Physiol Ann Arbor MI 48104 USA

Study of fast, GABA, receptor-mediated, inhibitory postsynaptic currents (TPSCs) in hippocampal dentate granule cells has suggested that properties of GABA(A) receptors influence the amplitude and time course of the IPSCs. This study describes the physiological properties of GABA(A) receptors present on hippocampal dentate granule cells-acutely isolated from 18- to 35-day-old rats. Rapid application of 1 mM GABA to outside-out macropatches excised from granule cells produced GABA(A) receptor currents with rapid rise time and biexponential decay of current after removal of GABA. After activation,: granule cell GABA(A) receptor currents desensitized incompletely. During a 400-ms application of 1 mM GABA(A) peak current only desensitized similar to 40%. In symmetrical chloride solutions there was no outward rectification of whole cell current. Activation rates and peak currents elicited by rapid application of GABA to macropatches were also similar at positive and negative holding potentials. However, deactivation of GABA(A) receptor currents was slower at positive holding potentials. When whole cell currents were recorded without ATP in the pipette, current run-down was not apparent for 30 min in 50% of neurons, but run-down appeared to start soon after access was established in the remaining neurons. When 2 mM ATP was included in the recording pipette no run-down was apparent in 30 min of recording. The efficacy and potency of GABA were lower in cells recorded with no ATP in the pipette and during run-down compared with those recorded with 2 mM ATP and no run-down.

关键词：腺苷三磷酸/药理学齿状回/细胞学齿状回/药物作用齿状回/代谢导电性电生理学神经元/药物作用神经元/代谢大鼠 Sprague-Dawley 受体 GABA-A/药物作用受体 GABA-A/生理学 γ氨基丁酸/药理学动物女(雌)性男(雄)性大鼠

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Translocation machinery for synthesis of integral membrane and secretory proteins in dendritic spines (vol 3, pg 311, 2000)

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NATURE NEUROSCIENCE 2000年第5期3卷 521-521页

作者： Pierce, JP van Leyen, K McCarthy, JB DepartmentofNeurologyandNeuroscience WeillMedicalCollegeofCornellUniversityNewYorkNewYork10021USA.

Proposes to explain the role of the local translation of dendrites in the invlovement of synthesized proteins at selective synapses in the generation of synapse-specific plasticity. Association of protein trans- location sites, ribosomes and luemnal ER proteins with neuronal endomemebrane system of dendrites and dendrite spines; Target options for synthesis of proteins; Assesment of potencial active translocation sites.

关键词：细胞质颗粒/化学细胞质颗粒/代谢细胞质颗粒/超微结构树突/化学树突/代谢树突/超微结构齿状回/代谢齿状回/超微结构内质网糙面/化学内质网糙面/代谢内质网糙面/超微结构膜蛋白质类/遗传学膜蛋白质类/代谢膜蛋白质类/分泌显微镜检查电子 RNA 信使/代谢大鼠 Sprague-Dawley 动物大鼠

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