@article{2591, abstract = {The occurrence and distribution of the preferred receptor for the neuropeptide, substance P (SP), the neurokinin-1 receptor (NK1R) was investigated in the vascular supply of the rat sciatic nerve. Messenger RNA for NK1R was demonstrated by RT-PCR in the epineurial layer where the majority of small arteries and arterioles feeding the endoneurial vasculature are located. Immunoreactivity to NK1R-protein was localized on the smooth muscle cells of these arterial vessels by means of immunofluorescence using a polyclonal NK1R antiserum. This muscular localization of NK1R explains the previously reported [Zochodne, D.W. and Ho, L.T., J. Physiol. 444 (1991) 615- 630] moderate vasoconstrictor rather than vasodilator effects of SP in this vascular bed.}, author = {Kummer, Wolfgang and Shigemoto, Ryuichi and Haberberger, Rainer}, issn = {0304-3940}, journal = {Neuroscience Letters}, number = {2}, pages = {119 -- 122}, publisher = {Elsevier}, title = {{Smooth muscle cells are the site of neurokinin-1 receptor localization in the arterial supply of the rat sciatic nerve}}, doi = {10.1016/S0304-3940(98)00926-4}, volume = {259}, year = {1999}, } @article{2592, abstract = {Metabotropic glutamate receptors (mGluRs) consist of eight different subtypes and exert their effects or second messengers and ion channels via G- proteins. The function of individual mGluR subtypes in the CNS, however, largely remains to be clarified. We examined the fear response of freezing after electric shock in wild-type and mGluR7(-/-) knockout littermates. Wild- type mice displayed freezing immediately after and 1 d after footshock. In comparison, mGluR7(-/-) knockout mice showed significantly reduced levels in both immediate postshock and delayed freezing responses. However, the knockout mice exhibited no abnormalities in pain sensitivity and locomotor activity. To further examine amygdala-dependent behavior, we performed conditioned taste aversion (CTA) experiments. In wild-type mice, the administration of saccharin followed by intraperitoneal injection of the malaise-inducing agent LiCl resulted in an association between saccharin and LiCl. This association caused strong CTA toward saccharin n contrast, mGluR7(-/-) knockout mice failed to associate between the taste and the negative reinforcer in CTA experiments. Again, the knockout mice showed no abnormalities in taste preference and in the sensitivity to LiCl toxicity. These results indicate that mGluR7 deficiency causes an impairment of two distinct amygdala-dependent behavioral paradigms. Immunohistochemical and immunoelectron-microscopic analyses showed that mGluR7 is highly expressed in amygdala and preferentially localized at the presynaptic axon terminals of glutamatergic neurons. Together, these findings strongly suggest that mGluR7 is involved in neural processes subserving amygdala-dependent averse responses.}, author = {Masugi, Miwako and Yokoi, Mineto and Shigemoto, Ryuichi and Muguruma, Keiko and Watanabe, Yasuyoshi and Sansig, Gilles and Van Der Putten, Herman and Nakanishi, Shigetada}, issn = {0270-6474}, journal = {Journal of Neuroscience}, number = {3}, pages = {955 -- 963}, publisher = {Society for Neuroscience}, title = {{Metabotropic glutamate receptor subtype 7 ablation causes deficit in fear response and conditioned taste aversion}}, doi = {10.1523/JNEUROSCI.19-03-00955.1999}, volume = {19}, year = {1999}, } @article{2593, abstract = {In cat and monkey, lamina I cells can be classified into three basic morphological types (fusiform, pyramidal, and multipolar), and recent intracellular labeling evidence in the cat indicates that fusiform and multipolar lamina I cells are two different types of nociceptive cells, whereas pyramidal cells are innocuous thermoreceptive-specific. Because earlier observations indicated that only nociceptive dorsal horn neurons respond to substance P (SP), we examined which morphological types of lamina I neurons express receptors for SP (NK-1r). We categorized NK-1r- immunoreactive (IR) lamina I neurons in serial horizontal sections from the cervical and lumbar enlargements of four monkeys. Consistent results were obtained by two independent teams of observers. Nearly all NK-1r-IR cells were fusiform (42%) or multipolar (43%), but only 6% were pyramidal (with 9% unclassified). We obtained similar findings in three monkeys in which we used double-labeling immunocytochemistry to identify NK-1r-IR and spinothalamic lamina I neurons retrogradely labeled with cholera toxin subunit b from the thalamus; most NK-1r-IR lamina I spinothalamic neurons were fusiform (48%) or multipolar (33%), and only 10% were pyramidal. In contrast, most (~75%) pyramidal and some (~25%) fusiform and multipolar lamina I spinothalamic neurons did not display NK-1r immunoreactivity. These data indicate that most fusiform and multipolar lamina I neurons in the monkey can express NK-1r, consistent with the idea that both types are nociceptive, whereas only a small proportion of lamina I pyramidal cells express this receptor, consistent with the previous finding that they are nonnociceptive. However, these findings also indicate that not all nociceptive lamina I neurons express receptors for SP.}, author = {Yu, Xiao and Zhang, En and Craig, Arthur and Shigemoto, Ryuichi and Ribeiro Da Silva, Alfredo and De Koninck, Yves}, issn = {0270-6474}, journal = {Journal of Neuroscience}, number = {9}, pages = {3545 -- 3555}, publisher = {Society for Neuroscience}, title = {{NK-1 receptor immunoreactivity in distinct morphological types of lamina I neurons of the primate spinal cord}}, doi = {10.1523/JNEUROSCI.19-09-03545.1999}, volume = {19}, year = {1999}, } @article{2594, abstract = {Substance P receptor (i.e. NK1)-like immunoreactive (SPR-LI) neurons were observed in the newborn and adult human spinal cord. Substance P receptor-like immunoreactive neuronal cell bodies were seen most frequently in lamina I, and were scattered throughout the remaining laminae of the dorsal horn and the area around the central canal. Some neurons in the intermediolateral nucleus also showed weak immunoreactivity. The pattern of distribution of SPR-LI neurons in the adult spinal cord was essentially the same as that in the newborn spinal cord. However, SPR-LI neurons cell bodies were seen much more frequently in the newborn than in the adult dorsal horn, especially in lamina II.}, author = {Ding, Yu and Zheng, Heng and Wang, Dian and Xu, Jun and Gong, Liang and Lü, Yan and Qin, Bing and Shi, Juan and Li, Hua and Li, Ji and Shigemoto, Ryuichi and Kaneko, Takeshi and Mizuno, Noboru}, issn = {0304-3940}, journal = {Neuroscience Letters}, number = {2}, pages = {133 -- 136}, publisher = {Elsevier}, title = {{The distribution of substance P receptor (NK1)-like immunoreactive neurons in the newborn and adult human spinal cord}}, doi = {10.1016/S0304-3940(99)00283-9}, volume = {266}, year = {1999}, } @article{2595, abstract = {Presynaptic metabotropic glutamate receptors (mGluRs) of group III constitute possible targets for putative neuroprotective drugs acting against glutamate excitotoxic insults. Indeed, in glutamatergic cerebellar granule neurones in culture, high concentrations of L-2-amino-4-phosphonobutyrate (L-AP4, above 0.3 mM, thus activating mGluR7) inhibit NMDA-induced cell death. In contrast, in striatal cultures which are enriched in GABAergic neurones, we show that high concentrations of L-AP4 increased neuronal death in control as well as in NMDA-stimulated cultures. Moreover, similar results were obtained with the GABA(B)R agonist, baclofen. Both the neuroprotective effects in cerebellar granule cells and the neurotoxic effects in striatal neurones were mediated via Gi-Go-coupled mGluRs, suggesting that these effects were probably mediated by mGluR7a or b and GABA(B)R expressed in these neurones. In striatal neurones, we found that L-AP4 and baclofen inhibited both basal and NMDA-stimulated GABA release. These inhibitions of GABA release may be responsible for the increase in basal and NMDA-stimulated neuronal death. Indeed, blockade of GABA(A) receptors with bicuculline increased neuronal death of control and NMDA-treated striatal cultures. Taken together, these results suggest that L-AP4 and baclofen, via mGluR7 and GABA(B)R, reduced the neuroprotective effect of GABA present in striatal cultures acting via GABA(A) receptors. Although caution must be taken when extrapolating from in vitro to in vivo situations, the present experiments and the recent observations that mGluR7 and GABA(B)R are expressed in heterologous synapses, should be taken into consideration when evaluating the neuroprotective action of future mGluR7 specific agonists or GABA(B)R specific antagonists.}, author = {Lafon Cazal, Mireille and Viennois, Gaëlle and Kühn, Rainer and Malitschek, Barbara and Pin, Jean and Shigemoto, Ryuichi and Bockaërt, Joël}, issn = {0028-3908}, journal = {Neuropharmacology}, number = {10}, pages = {1631 -- 1640}, publisher = {Elsevier}, title = {{mGluR7-like receptor and GABA(B) receptor activation enhance neurotoxic effects of N-methyl-D-aspartate in cultured mouse striatal GABAergic neurones}}, doi = {10.1016/S0028-3908(99)00124-0}, volume = {38}, year = {1999}, } @article{2596, abstract = {A γ-aminobutyric acid (GABA)(B) receptor (named GABA(B)R1) has been recently cloned in the rat and human brain and two variants generated by alternative RNA splicing were identified. In the present study, we addressed the question as to whether these variants contribute to the diversity of GABA(B) receptor-mediated physiological responses and constitute real receptor subtypes with distinct functions. To this aim, we have mapped the GABA(B)R1 (R1a) and GABA(B)R1b (R1b) transcript distribution in the rat brain using in situ hybridization. We have compared the mRNA distribution with the distribution of [ 3H]CGP54626-labeled binding GABA(B)R1 receptor sites as assessed in adjacent cryosections by quantitative autoradiography. We found that GABA(B) receptor transcripts and binding sites are expressed in the brain in almost all neuronal cell populations. Expression in glial cells, if any, is marginal. We observed a good parallelism between GABA(B)R1 mRNA transcripts and binding sites in broad neuroanatomical entities with highest densities in hippocampus, thalamic nuclei, and cerebellum. By contrast, R1a and R1b transcripts exhibit marked differences in their regional and cellular distribution pattern. A typical example is the cerebellum with an almost exclusive expression of R1b in the Purkinje cells and of R1a in the granule, stellate, and basket cells. Data pointing at a pre- versus postsynaptic localization for R1a and R1b, respectively, at some neuronal sites are presented. }, author = {Bischoff, Serge and Leonhard, Sabine and Reymann, Nicole and Schuler, Valérie and Shigemoto, Ryuichi and Kaupmann, Klemens and Bettler, Bernhard}, issn = {0021-9967}, journal = {Journal of Comparative Neurology}, number = {1}, pages = {1 -- 16}, publisher = {Wiley-Blackwell}, title = {{Spatial distribution of GABA(B)R1 receptor mRNA and binding sites in the rat brain^}}, doi = {10.1002/(SICI)1096-9861(19990913)412:1<1::AID-CNE1>3.0.CO;2-D}, volume = {412}, year = {1999}, } @article{2597, abstract = {Metabotropic glutamate receptors (mGlus) are known to modulate synaptic transmission in various pathways of the central nervous system, but the exact mechanisms by which this modulation occurs remain unclear. Here we utilise electrophysiological and immunocytochemical techniques on cultured autaptic hippocampal neurones to investigate the mechanism of action and distribution of mGlus. Agonists at all three groups of mGlus depressed glutamatergic transmission, whereas only agonists at group I mGlus depressed GABAergic transmission. Agonists at all mGlus failed to modulate Ca2+ and K+ channels in glutamatergic autapses whereas an agonist at group III mGlus did depress the frequency of miniature excitatory postsynaptic currents (mEPSCs). Agonists failed to modulate Ca2+ or K+ channels and miniature inhibitory postsynaptic currents (mIPSCs) in GABAergic autapses. Distribution studies using selective antibodies revealed punctate staining for group III mGlus that co-localised with the synaptic marker, synaptophysin. Staining for the remaining mGlus was more diffuse throughout the soma and processes with little co-localisation with synaptophysin. The distribution of the group III receptors is consistent with the direct 'downstream' modulation of mEPSCs, although the exact mechanism of action for the remaining receptors remains unclear.}, author = {Bushell, Trevor and Lee, Chong and Shigemoto, Ryuichi and Miller, Richard}, issn = {0028-3908}, journal = {Neuropharmacology}, number = {10}, pages = {1553 -- 1567}, publisher = {Elsevier}, title = {{Modulation of synaptic transmission and differential localisation of mGlus in cultured hippocampal autapses}}, doi = {10.1016/S0028-3908(99)00103-3}, volume = {38}, year = {1999}, } @inproceedings{2711, abstract = {We study the long time evolution of a quantum particle in a Gaussian random environment. We show that in the weak coupling limit the Wigner distribution of the wave function converges to the solution of a linear Boltzmann equation globally in time. The Boltzmann collision kernel is given by the Born approximation of the quantum scattering cross section.}, author = {Erdös, László}, booktitle = {Proceedings of the 7th QMath Conference}, isbn = {9783034897549}, location = {Prague, Czech Republik}, pages = {233 -- 242}, publisher = {World Scientific Publishing}, title = {{Linear Boltzmann equation as the weak coupling limit of the random Schrödinger equation}}, doi = {10.1007/978-3-0348-8745-8_20}, volume = {108}, year = {1999}, } @article{2730, abstract = {We give the leading order semiclassical asymptotics for the sum of the negative eigenvalues of the Pauli operator (in dimension two and three) with a strong non-homogeneous magnetic field. This result can be used to prove that the magnetic Thomas-Fermi theory gives the leading order ground state energy of large atoms. We develop a new localization scheme well suited to the anisotropic character of the strong magnetic field. We also use the basic Lieb-Thirring estimate obtained earlier (1996). (orig.) 19 refs.}, author = {Erdös, László and Solovej, Jan}, issn = {0012-7094}, journal = {Duke Mathematical Journal}, number = {1}, pages = {127 -- 173}, publisher = {Duke University Press}, title = {{Semiclassical eigenvalue estimates for the Pauli operator with strong nonhomogeneous magnetic fields, I: Nonasymptotic Lieb-Thirring-type estimate}}, doi = {10.1215/S0012-7094-99-09604-7}, volume = {96}, year = {1999}, } @article{2783, abstract = {Pattern formation in a layer of fluid heated from below is an example of macroscopic ordering in continuous media. Here we show that in a relatively compact experimental version of the problem, a rich and diverse set of stable flows can be found. These flows, many of which are novel, can be categorized and understood in terms of their symmetry properties. This approach shows promise for providing insight into the more complicated fluid motion that occurs as the lateral dimension of the layer is increased.}, author = {Hof, Björn and Lucas, Peter and Mullin, Tom}, issn = {0031-9171}, journal = {Physics of Fluids}, number = {10}, pages = {2815 -- 2817}, publisher = {American Institute of Physics}, title = {{Flow state multiplicity in convection}}, doi = {10.1063/1.870178 }, volume = {11}, year = {1999}, } @article{2864, abstract = {Using an electrospray tandem mass spectrometer as a concentration-sensitive detector, a method has been developed to quantify femtomole amounts of plant growth regulators (i.e. isoprenoid type cytokinins, zeatin, dihydrozeatin, isopentenyladenine and their respective riboside and glucoside analogues) and the second messenger adenosine 3':5'-cyclic monophosphate (3':5'-cAMP). Miniaturisation of the chromatographic setup using capillary high performance liquid chromatographic (HPLC) ion spray mass spectrometry increased the sensitivity to the low femtomole region. Application of automated capillary column switching allowed the introduction of large injection volumes into the HPLC system. Aliquots (25 μL) were injected into one dimension of the HPLC set-up and stacked onto a micro pre-column. By means of mobile phase switching the pre-column was back-flushed to introduce the analytes onto the analytical column. For cytokinin analysis positive electrospray ionisation was used and resulted in 2.5-25 fmol detection limits. Cyclic nucleotides were separated under ion-pair conditions using tetrabutyl ammonium bromide as ion-pair reagent and were detected under negative electrospray ionisation conditions. Here a 25 fmol detection limit was determined. Following this approach, cytokinins and 3':5'-cAMP extracted from only mg amounts of apical shoot meristem and chloroplasts obtained from Nicotiana tabacum cv. Petit Havana SR1 were identified and quantified.}, author = {Witters, Erwin and Vanhoutte, Koen and Dewitte, Walter and Macháčková, Ivana and Benková, Eva and Van Dongen, Walter and Esmans, Eddy and Van Onckelen, Henri}, issn = {0958-0344}, journal = {Phytochemical Analysis}, number = {3}, pages = {143 -- 151}, publisher = {Wiley-Blackwell}, title = {{Analysis of cyclic nucleotides and cytokinins in minute plant samples using phase system switching capillary electrospray liquid chromatography tandem mass spectrometry}}, doi = {10.1002/(SICI)1099-1565(199905/06)10:3<143::AID-PCA441>3.0.CO;2-G}, volume = {10}, year = {1999}, } @article{2865, abstract = {Although cytokinins (CKs) affect a number of processes connected with chloroplasts, it has never been rigorously proven that chloroplasts contain CKs. We isolated intact chloroplasts from tobacco (Nicotiana tabacum L. cv SR1) and wheat (Triticum aestivum L. cv Ritmo) leaves and determined their CKs by liquid chromatography/tandem mass spectroscopy. Chloroplasts from both species contained a whole spectrum of CKs, including free bases (zeatin and isopentenyladenine), ribosides (zeatin riboside, and isopentenyladenosine), ribotides (isopentenyladenosine-5′-monophosphate, zeatin riboside-5′-monophosphate, and dihydrozeatin riboside-5′-monophosphate), and N-glucosides (zeatin-N 9-glucoside, dihydrozeatin-N 9-glucoside, zeatin-N 7-glucoside, and isopentenyladenine-N-glucosides). In chloroplasts there was a moderately higher relative amount of bases, ribosides, and ribotides than in leaves, and a significantly increased level ofN 9-glucosides of zeatin and dihydrozeatin. Tobacco and wheat chloroplasts were prepared from leaves at the end of either a dark or light period. After a dark period, chloroplasts accumulated more CKs than after a light period. The differences were moderate for free bases and ribosides, but highly significant for glucosides. Tobacco chloroplasts from dark-treated leaves contained zeatin riboside-O-glucoside and dihydrozeatin riboside-O-glucoside, as well as a relatively high CK oxidase activity. These data show that chloroplasts contain a whole spectrum of CKs and the enzymatic activity necessary for their metabolism. }, author = {Benková, Eva and Witters, Erwin and Van Dongen, Walter and Kolář, Jan and Motyka, Václav and Brzobohatý, Břetislav and Van Onckelen, Henri and Macháčková, Ivana}, issn = {0032-0889}, journal = {Plant Physiology}, number = {1}, pages = {245 -- 251}, publisher = {American Society of Plant Biologists}, title = {{Cytokinins in tobacco and wheat chloroplasts. Occurrence and changes due to light/dark treatment}}, doi = {10.1104/pp.121.1.245}, volume = {121}, year = {1999}, } @book{3137, abstract = {This volume provides an overview of glutamate receptors and their role in excitatory neurotransmission. It focusses on three aspects. First, it describes the functional, molecular, and pharmacological properties of glutamate receptors (AMPA, NMDA, and kainate receptors). Second, it gives a survey how these receptors are involved in synaptic transmission at different glutamatergic synapses in the mammalian CNS. Finally, it adresses how overactivation of glutamate receptors can lead to excitotoxic cell death, and emphasizes the importance of glutamate receptors as potential therapeutical targets. The chapters, written by leading scientists, give accurate summaries of facets that have emerged recently in this field. The book demonstrates the strength of a multidisciplinary approach involving physiology, pharmacology, and molecular biology. It will be useful for other scientists in and outside the field, lecturers and students at different educational levels.}, editor = {Jonas, Peter M and Monyer, Hannah}, isbn = {978-3-642-08539-0}, issn = {1865-0325}, pages = {XXII, 535}, publisher = {Springer}, title = {{Ionotropic Glutamate Receptors in the CNS}}, doi = {10.1007/978-3-662-08022-1}, volume = {141}, year = {1999}, } @article{3148, abstract = {Accurate proteolytic processing of neuropeptide and peptide hormone precursors by members of the kexin/furin family of proteases is key to determining both the identities and activities of signaling peptides. Here we identify amontillado (amon), the Drosophila melanogaster homolog of the mammalian neuropeptide processing protease PC2, and show that in contrast to vertebrate PC2, amontillado expression undergoes extensive regulation in the nervous system during development. In situ hybridization reveals that expression of amontillado is restricted to the final stages of embryogenesis when it is found in anterior sensory structures and in only 168 cells in the brain and ventral nerve cord. After larvae hatch from their egg shells, the sensory structures and most cells in the CNS turn off or substantially reduce amontillado expression, suggesting that amontillado plays a specific role late in embryogenesis. Larvae lacking the chromosomal region containing amontillado show no gross anatomical defects and respond to touch. However, such larvae show a greatly reduced frequency of a hatching behavior of wild- type Drosophila in which larvae swing their heads, scraping through the eggshell with their mouth hooks. Ubiquitous expression of amontillado can restore near wild-type levels of this behavior, whereas expression of amontillado with an alanine substitution for the catalytic histidine cannot. These results suggest that amontillado expression is regulated as part of a programmed modulation of neural signaling that controls hatching behavior by producing specific neuropeptides in particular neurons at an appropriate developmental time.}, author = {Siekhaus, Daria E and Fuller, Robert}, issn = {0270-6474}, journal = {Journal of Neuroscience}, number = {16}, pages = {6942 -- 6954}, publisher = {Society for Neuroscience}, title = {{A role for amontillado the Drosophila homolog of the neuropeptide precursor processing protease PC2 in triggering hatching behavior}}, doi = {10.1523/jneurosci.19-16-06942.1999}, volume = {19}, year = {1999}, } @article{3444, abstract = {This study examined intermittent, high-frequency (100-200 Hz) oscillatory patterns in the CA1 region of the hippocampus in the absence of theta activity, i.e., during and in between sharp wave (SPW) bursts. Pyramidal and interneuronal activity was phase-locked not only to large amplitude (>7 SD from baseline) oscillatory events, which are present mainly during SPWs, but to smaller amplitude (<4 SD) patterns, as well. Large-amplitude events were in the 140-200 Hz, "ripple" frequency range. Lower-amplitude events, however, contained slower, 100-130 Hz ("slow") oscillatory patterns. Fast ripple waves reversed just below the CA1 pyramidal layer, whereas slow oscillatory potentials reversed in the stratum radiatum and/or in the stratum oriens. Parallel CA1-CA3 recordings revealed correlated CA3 field and unit activity to the slow CA1 waves but not to fast ripple waves. These findings suggest that fast ripples emerge in the CA1 region, whereas slow (100-130 Hz) oscillatory patterns are generated in the CA3 region and transferred to the CA1 field.}, author = {Csicsvari, Jozsef L and Hirase, Hajima and Czurkó, András and Mamiya, Akira and Buzsáki, György}, issn = {0270-6474}, journal = {Journal of Neuroscience}, number = {16}, publisher = {Society for Neuroscience}, title = {{Fast network oscillations in the hippocampal CA1 region of the behaving rat}}, doi = {10.1523/JNEUROSCI.19-16-j0001.1999}, volume = {19}, year = {1999}, } @article{3445, abstract = {The medial septal region and the hippocampus are connected reciprocally via GABAergic neurons, but the physiological role of this loop is still not well understood. In an attempt to reveal the physiological effects of the hippocamposeptal GABAergic projection, we cross-correlated hippocampal sharp wave (SPW) ripples or theta activity and extracellular units recorded in the medial septum and diagonal band of Broca (MSDB) in freely moving rats. The majority of single MSDB cells (60%) were significantly suppressed during SPWs. Most cells inhibited during SPW (80%) fired rhythmically and phase-locked to the negative peak of the CA1 pyramidal layer theta waves. Because both SPW and the negative peak of local theta waves correspond to the maximum discharge probability of CA1 pyramidal cells and interneuron classes, the findings indicate that the activity of medial septal neurons can be negatively (during SPW) or positively (during theta waves) correlated with the activity of hippocampal interneurons. We hypothesize that the functional coupling between medial septal neurons and hippocampal interneurons varies in a state-dependent manner.}, author = {Dragoi, George and Carpi, Daniel and Recce, Michael and Csicsvari, Jozsef L and Buzsáki, György}, issn = {0270-6474}, journal = {Journal of Neuroscience}, number = {14}, pages = {6191 -- 6199}, publisher = {Society for Neuroscience}, title = {{Interactions between hippocampus and medial septum during sharp waves and theta oscillation in the behaving rat}}, doi = {10.1523/JNEUROSCI.19-14-06191.1999}, volume = {19}, year = {1999}, } @inbook{3456, abstract = {L-a-amino-3-hydroxy-5-methyl-4-isoxazolepropionate receptors (AMPARs) and N-methyl-D-aspartate receptors (NMDARs) are the two major types of postsynaptic glutamate receptors (GluRs) that mediate excitatory synaptic transmission in the mammalian central nervous system (CNS). Both AMPARs and NMDARs are multimeric proteins, probably tetramers, formed by a variety of molecularly distinct subunits. AMPARs can be assembled from four types of subunits, termed GIuR-A, -B, -C, and -D (or, in an alternative nomenclature, G1uR1, G1uR2, GluR3, and G1uR4). Additional molecular diversity of AMPARs is generated by alternative splicing of the flip-flop module and RNA editing at the Q/R and R/G site. NMDARs are heteromers primarily assembled from NR1 subunits and NR2A, B, C, or D subunits. Various splice variants have been identified for the NR1 subunit, and a new NR3 subunit has been discovered recently. Considering all combinatorial possibilities, the molecular diversity of glutamate-receptor channels is considerable (HOLLMANN, this volume).}, author = {Monyer, Hannah and Jonas, Peter M and Rossier, Jean}, booktitle = {Ionotropic Glutamate Receptors in the CNS}, editor = {Jonas, Peter M and Monyer, Hannah}, isbn = {9783642085390}, pages = {309 -- 339}, publisher = {Springer}, title = {{Molecular determinants controlling functional properties of AMPARs and NMDARs in the mammalian CNS}}, doi = {10.1007/978-3-662-08022-1_9}, volume = {141}, year = {1999}, } @inbook{3457, abstract = {Principal neurons and interneurons are the two main classes of cells in cortical neuronal networks. Principal neurons (granule cells or pyramidal neurons) have transregional axonal projections and release glutamate onto their postsynaptic target cells. In contrast, interneurons have local, but often extensive, axonal arborizations and use γ-aminobutyric acid (GABA) as a transmitter. Although interneurons represent only approximately 10% of the neuronal population, they control the electrical activity of the entire network (FREUND and BUZSÁKI 1996). Interneurons forming inhibitory synapses on the somata or axon initial segments of their postsynaptic target cells are thought to set the threshold of action potential initiation (MILES et al. 1996) and can synchronize the collective activities of large principal neuron ensembles (COBB et al. 1995). In contrast, interneurons establishing inhibitory synapses mainly on dendrites could suppress dendritic Na+ or Ca2+ spikes (BUZSÁKI et al. 1996; MILES et al. 1996) and, thus, regulate plasticity at glutamatergic synapses in the cortex (DAVIES et al.1991).}, author = {Geiger, Jörg and Roth, Arnd and Taskin, Birol and Jonas, Peter M}, booktitle = {Ionotropic Glutamate Receptors in the CNS}, editor = {Monyer, Hannah and Jonas, Peter M}, isbn = {9783642085390}, pages = {363 -- 398}, publisher = {Springer}, title = {{Glutamate-mediated synaptic excitation of cortical interneurons}}, doi = {10.1007/978-3-662-08022-1_11}, volume = {141}, year = {1999}, } @article{3515, abstract = {Oscillations in neuronal networks are assumed to serve various physiological functions, from coordination of motor patterns to perceptual binding of sensory information. Here, we describe an ultra-slow oscillation (0.025 Hz) in the hippocampus. Extracellular and intracellular activity was recorded from the CA1 and subicular regions in rats of the Wistar and Sprague-Dawley strains. anesthetized with urethane. in a subgroup of Wistar rats (23%), spontaneous afterdischarges (4.7 +/- 1.6 s) occurred regularly at 40.8 +/- 15.7 s. The afterdischarge was initiated by a fast increase of population synchrony (100-250 Hz oscillation; “tonic” phase), followed by large-amplitude rhythmic waves and associated action potentials at gamma and beta frequency (15-50 Hz; “clonic” phase). The afterdischarges were bilaterally synchronous and terminated relatively abruptly without post-ictal depression. Single-pulse stimulation of the commissural input could trigger afterdischarges, but only at times when they were about to occur. Commissural stimulation evoked inhibitory postsynaptic potentials in pyramidal cells. However, when the stimulus triggered an afterdischarge, the inhibitory postsynaptic potential was absent and the cells remained depolarized during most of the afterdischarge. Afterdischarges were not observed in the Sprague-Dawley rats. Long-term analysis of interneuronal activity in intact, drug-free rats also revealed periodic excitability changes in the hippocampal network at 0.025 Hz. These findings indicate the presence of an ultra-slow oscillation in the hippocampal formation. The ultra-slow clock induced afterdischarges in susceptible animals. We hypothesize that a transient failure of GABAergic inhibition in a subset of Wistar rats is responsible for the emergence of epileptiform patterns. (C) 1999 IBRO. Published by Elsevier Science Ltd.}, author = {Penttonen, Markku and Nurminen, Nina and Miettinen, Riitta and Sirviö, Jouni and Henze, Darrell and Csicsvari, Jozsef L and Buzsáki, György}, issn = {0306-4522}, journal = {Neuroscience}, number = {3}, pages = {735 -- 743}, publisher = {Elsevier}, title = {{Ultra-slow oscillation (0.025 Hz) triggers hippocampal afterdischarges in Wistar rats}}, doi = {10.1016/S0306-4522(99)00367-X}, volume = {94}, year = {1999}, } @article{3518, abstract = {Information in neuronal networks may be represented by the spatiotemporal patterns of spikes. Here we examined the temporal coordination of pyramidal cell spikes in the rat hippocampus during slow-wave sleep. In addition, rats were trained to run in a defined position in space (running wheel) to activate a selected group of pyramidal cells. A template-matching method and a joint probability map method were used for sequence search. Repeating spike sequences in excess of chance occurrence were examined by comparing the number of repeating sequences in the original spike trains and in surrogate trains after Monte Carlo shuffling of the spikes. Four different shuffling procedures were used to control for the population dynamics of hippocampal neurons. Repeating spike sequences in the recorded cell assemblies were present in both the awake and sleeping animal in excess of what might be predicted by random variations. Spike sequences observed during wheel running were “replayed” at a faster timescale during single sharp-wave bursts of slow-wave sleep. We hypothesize that the endogenously expressed spike sequences during sleep reflect reactivation of the circuitry modified by previous experience. Reactivation of acquired sequences may serve to consolidate information.}, author = {Nádasdy, Zoltán and Hirase, Hajima and Czurkó, András and Csicsvari, Jozsef L and Buzsáki, György}, issn = {0270-6474}, journal = {Journal of Neuroscience}, number = {21}, pages = {9497 -- 9507}, publisher = {Society for Neuroscience}, title = {{Replay and time compression of recurring spike sequences in the hippocampus}}, doi = {10.1523/JNEUROSCI.19-21-09497.1999}, volume = {19}, year = {1999}, }