麩胺酸是負責脊椎動物大腦中樞神經系統中主要的興奮性神經傳導物質。離子通道型麩胺酸受器依其藥理學特性可分為三種次型，分別是AMPA、kainate及NMDA受器。吳郭魚魚腦中會表現8種不同AMPA受器的組成單元(fGluR1~4a及fGluR1~4b。不同於哺乳動物AMPA受器單元，單獨表現的fGluR1a(i) (i代表flip形式受器單元)麩胺酸刺激只在添加抑制desensitization藥物cyclothiazide下才能測得微弱電流。本論文想了解(1)fGluR1a(i)是否會與其他AMPA單元形成異構型受器，(2)若能形成異構型受器這些含fGluR1a(i)的異構型受器特性是較近似於fGluR1a(i)或較類似共組形成異構型受器之其他AMPA受器單元特性?我們以電生理學方法分析爪蟾卵母細胞注射不同混合比例所表現的fGluR2b(i)/fGluR3a(o) (i及o分別代表flip及flop形式受器單元)及fGluR1a(o)/fGluR2b(i)顯示fGluR3a(o)及fGluR1a(o)皆能與fGluR2b(i)形成異構型受器，且特性相似於哺乳類GluR2/GluR3及GluR1/GluR2受器。分析不同混合比例所表現的fGluR1a(i)/fGluR2□(i)顯示兩者能形成異構型受器，而此種異構型受器不具活性或活性很弱。分析不同混合比例所表現的fGluR1aR(i)/fGluR3a(o)顯示兩者也能形成異構型受器，而此種異構型受器的活性也很低。含fGluR1□a(i)及fGluR1aR(i)單元的異構型AMPA受器的活性低特性較接近fGluR1a(i)，與哺乳類GluR1/GluR2及GluR2/GluR3異構型受器的特性不同。
GluRd2屬於離子通道型麩胺酸受器的一種，基因發生lurcher突變的老鼠GluRd2 (GluRd2Lc)會有持續性離子通道活性而GluRd2沒有這個現象。我們想知道斑馬魚的GluRd2及GluRd2 Lc是否也有相同的特性，於是將cRNA注射到爪蟾卵母細胞裡，經過電生理學方法分析顯示斑馬魚GluRd2 Lc具有持續性離子通道活性而GluRd2不具活性，特性與老鼠相同。

L-glutamate is the major excitatory neurotransmitter in the vertebrate central nervous system. Ionotropic glutamate receptors are divided into three subtypes, AMPA-, kainate- and NMDA-preferring receptors. Oreochomis mossambicus (tilapia) expresses eight AMPA receptor subunits (fGluR1~4a and fGluR1~4b). The glutamate-activated currents of fGluR1a(i), i represents the flip form, were only detected in the presence of the desensitization blocker, cyclothiazide. The goals of this research are to study if the tilapia fGluR1a(i) can form heteromeric receptors with other AMPA subunits, and the properties of the heteromeric AMPA receptors containing fGluR1a(i). The current-voltage (I-V) relationships of fGluR2b(i)/fGluR3a(o), o represents the flop form, and fGluR1a(o)/fGluR2b(i) were determined in Xenopus oocytes co-injected with the mixed cRNA in various ratios. The results demonstrated that fGluR3a(o) and fGluR1a(o) could individually form heteromeric receptors with fGluR2b(i). Moreover, the I-V relationships of the tilapia fGluR2b(i)/fGluR3a(o) and fGluR1a(o)/fGluR2b(i) were similar to the mammalian GluR2/GluR3 and GluR1/GluR2 receptors. Similar analysis indicated that fGluR1a(i)/fGluR2b(i) and fGluR1aR(i)/fGluR3a(o) could form heteromeric receptors; however, unlike the mammalian GluR1/GluR2 and GluR2/GluR3 receptors, the channel activities of fGluR1a(i)/fGluR2b(i) and fGluR1aR(i)/fGluR3a(o) were very low.
GluR□2 is one of the ionotropic glutamate receptors. The channel activity of GluR□2 has not been successfully detected by application of any known glutamate receptor agonists at present. On the other hand, a spontaneous GluR□2 mutation of mouse, the GluR□2Lc, has been shown to express a constitutive cation channel. Here, we also studied the zebrafish GluR□2 and GluR□2Lc. Xenoupus oocytes expressing these zebrafish GluR□2 channels displayed properties similar to their mammalian counterparts.

Armstrong, N., and Gouaux, E. (2000). Mechanisms for activation and antagonism of an AMPA-sensitive glutamate receptor: crystal structures of the GluR2 ligand binding core. Neuron 28, 165-181.
Ayalon, G., and Stern-Bach, Y. (2001). Functional assembly of AMPA and kainate receptors is mediated by several discrete protein-protein interactions. Neuron 31, 103-113.
Bettler, B., Boulter, J., Hermans-Borgmeyer, I., O'Shea-Greenfield, A., Deneris, E. S., Moll, C., Borgmeyer, U., Hollmann, M., and Heinemann, S. (1990). Cloning of a novel glutamate receptor subunit, GluR5: expression in the nervous system during development. Neuron 5, 583-595.
Bettler, B., and Mulle, C. (1995). Review : Neurotransmitter receptors II : AMPA and kainite receptors. Neuropharmacology 34, 123-139.
Bolton, M. M., Blanpied, T. A., and Ehlers, M. D. (2000). Localization and stabilization of ionotropic glutamate receptors at synapses. Cell Mol Life Sci 57, 1517-1525.
Brorson, J. R., Li, D., and Suzuki, T. (2004). Selective expression of heteromeric AMPA receptors driven by flip-flop differences. J Neurosci 24, 3461-3470.
Chang, H. M., Wu, Y. M., Chang, Y. C., Hsu, Y. C., Hsu, H. Y., Chen, Y. C., and Chow, W. Y. (1998). Molecular and electrophysiological characterizations of fGluR3 alpha, an ionotropic glutamate receptor subunit of a teleost fish. Brain Res Mol Brain Res 57, 211-220
Collingridge, G. L., and Lester, R. A. J.(1987). NMDA receptors-their role in long term potentiation. Trends Neurosci. 10, 288-293.
Collingridge, G. L., and Lester, R. A. J.(1989). Excitatory amino acid receptors in the vertebrate central nervous system. Pharmacol. Rev. 41, 143-210
Das, S., Sasaki, Y. F., Rothe, T., Premkumar, L. S., Takasu, M., Crandall, J. E., Dikkes, P., Conner, D. A., Rayudu, P. V., Cheung, W., et al. (1998). Increased NMDA current and spine density in mice lacking the NMDA receptor subunit NR3A. Nature 393, 377-381.
Egebjerg, J., B., Hermans-Borgmeyer, I., Heinemann, S. (1991). Cloning of a cDNA for a glutamate receptor subunit activated kainate but not AMPA. Nature 351, 745-748.
Greger, I. H., Khatri, L., Kong, X., and Ziff, E. B. (2003). AMPA receptor tetramerization is mediated by Q/R editing. Neuron 40, 763-774
Hollmann, M., Hartley, M., and Heinemann, S. (1991). Ca2+ permeability of KA-AMPA--gated glutamate receptor channels depends on subunit composition. Science 252, 851-853.

Hollmann, M., and Heinmann, S.(1994). Cloned glutamate receptors. Annu. Rev. Neurosci. 17, 31-108
Hollmann, M., Maron, C., and Heinemann, S. (1994). N-glycosylation site tagging suggests a three transmembrane domain topology for the glutamate receptor GluR1. Neuron 13, 1331-1343.
Hume, R. I., Dingledine, R., and Heinemann, S. F. (1991). Identification of a site in glutamate receptor subunits that controls calcium permeability. Science 253, 1028-1031.
Jonas, P., and Burnashev, N. (1995). Molecular mechanisms controlling calcium entry through AMPA-type glutamate receptor channels. Neuron 15, 987-990
Kashiwabuchi, N., Ikeda, K., Araki, K., Hirano, T., Shibuki, K., Takayama, C., Inoue, Y., Kutsuwada, T., Yagi, T., Kang, Y., and et al. (1995). Impairment of motor coordination, Purkinje cell synapse formation, and cerebellar long-term depression in GluR delta 2 mutant mice. Cell 81, 245-252
Keinanen, K., Wisden, W., Sommer, B., Werner, P., Herb, A., Verdoorn, T. A., Sakmann, B., and Seeburg, P. H. (1990). A family of AMPA-selective glutamate receptors. Science 249, 556-560.
Kohda, K., Wang, Y., and Yuzaki, M. (2000). Mutation of a glutamate receptor motif reveals its role in gating and delta2 receptor channel properties. Nat Neurosci 3, 315-322.
Kung, S. S., Wu, Y. M., and Chow, W. Y. (1996). Characterization of two fish glutamate receptor cDNA molecules: absence of RNA editing at the Q/R site. Brain Res Mol Brain Res 35, 119-130.
Lemaire, P., Garrett, N., and Gurdon, J. B. (1995). Expression cloning of Siamois, a Xenopus homeobox gene expressed in dorsal-vegetal cells of blastulae and able to induce a complete secondary axis. Cell 81, 85-94.
Lomeli, H., Sprengel, R., Laurie, D.J., Kohr, G., Herb, A., Seeburg, P.H., Wisden, W., (1993). The rat delta-1 and delta-2 subunits extend the excitatory amino acid receptor famiky. FEBS Lett. 315, 318-322.
Lomeli, H., Mosbacher, J., Melcher, T., Hoger, T., Geiger, J. R., Kuner, T., Monyer, H., Higuchi, M., Bach, A., and Seeburg, P. H. (1994). Control of kinetic properties of AMPA receptor channels by nuclear RNA editing. Science 266, 1709-1713.
Madden, D. R. (2002). The structure and function of glutamate receptor ion channels. Nat Rev Neurosci 3, 91-101.
Mansour, M., Nagarajan, N., Nehring, R. B., Clements, J. D., and Rosenmund, C. (2001). Heteromeric AMPA receptors assemble with a preferred subunit stoichiometry and spatial arrangement. Neuron 32, 841-853
Matsuda, S., and Yuzaki, M. (2002). Mutation in hotfoot-4J mice results in retention of delta2 glutamate receptors in ER. Eur J Neurosci 16, 1507-1516.
Mikami, Y., Yoshida, T., Matsuda, N., and Mishina, M. (2004). Expression of zebrafish glutamate receptor delta2 in neurons with cerebellum-like wiring. Biochem Biophys Res Commun 322, 168-176
Monaghan, D.T.,Bridges, R.J., and Cotman, C.W. (1989). The excitatory amino acid receptor: their classes, pharmacology, and distinct properties in the function of the central nervous system. Annu. Rev. Pharmacol. 29, 365-402.
Morris, R. G. M. (1989). Synaptic plasticity and learning ; selective impairment of learning in rats and blockage long-term potentiation in vivo by the N-methy-D-asparate receptor antagonist AP5. J. Neurosci. 9, 3040-3057.
Nakanishi, N., Shneider, N. A., and Axel, R. (1990). A family of glutamate receptor genes: evidence for the formation of heteromultimeric receptors with distinct channel properties. Neuron 5, 569-581.
O'Hara, P. J., Sheppard, P. O., Thogersen, H., Venezia, D., Haldeman, B. A., McGrane, V., Houamed, K. M., Thomsen, C., Gilbert, T. L., and Mulvihill, E. R. (1993). The ligand-binding domain in metabotropic glutamate receptors is related to bacterial periplasmic binding proteins. Neuron 11, 41-52.
Partin, K. M., Patneau, D. K., and Mayer, M. L. (1994). Cyclothiazide differentially modulates desensitization of alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor splice variants. Mol Pharmacol 46, 129-138.
Schiffer, H. H., Swanson, G. T., and Heinemann, S. F. (1997). Rat GluR7 and a carboxy-terminal splice variant, GluR7b, are functional kainate receptor subunits with a low sensitivity to glutamate. Neuron 19, 1141-1146.
Schoepp, D.D., and Conn, P. J. (1993). Metabotropic glutamate receptor in brain function and pathology. Trend pharmacol. Sci. 14. 13-20.
Sommer, B., Keinanen, K., Verdoorn, T. A., Wisden, W., Burnashev, N., Herb, A., Kohler, M., Takagi, T., Sakmann, B., and Seeburg, P. H. (1990). Flip and flop: a cell-specific functional switch in glutamate-operated channels of the CNS. Science 249, 1580-1585.
Verdoorn, T. A., Burnashev, N., Monyer, H., Seeburg, P. H., and Sakmann, B. (1991). Structural determinants of ion flow through recombinant glutamate receptor channels. Science 252, 1715-1718.
Wang, Y., Matsuda, S., Drews, V., Torashima, T., Meisler, M. H., and Yuzaki, M. (2003). A hot spot for hotfoot mutations in the gene encoding the delta2 glutamate receptor. Eur J Neurosci 17, 1581-1590.

Wenthold, R. J., Petralia, R. S., Blahos, J., II, and Niedzielski, A. S. (1996). Evidence for multiple AMPA receptor complexes in hippocampal CA1/CA2 neurons. J Neurosci 16, 1982-1989.
Wood, M. W., VanDongen, H. M., and VanDongen, A. M. (1995). Structural conservation of ion conduction pathways in K channels and glutamate receptors. Proc Natl Acad Sci U S A 92, 4882-4886.
Wu, Y. M., Kung, S. S., Chen, J., and Chow, W. Y. (1996). Molecular analysis of cDNA molecules encoding glutamate receptor subunits, fGluR1 alpha and fGluR1 beta, of Oreochromis sp. DNA Cell Biol 15, 717-725.
Yue, Z., Horton, A., Bravin, M., DeJager, P. L., Selimi, F., and Heintz, N. (2002). A novel protein complex linking the delta 2 glutamate receptor and autophagy: implications for neurodegeneration in lurcher mice. Neuron 35, 921-933.
Yuzaki, M. (2003). The delta2 glutamate receptor: 10 years later. Neurosci Res 46, 11-22.
Zuo, J., De Jager, P. L., Takahashi, K. A., Jiang, W., Linden, D. J., and Heintz, N. (1997). Neurodegeneration in Lurcher mice caused by mutation in delta2 glutamate receptor gene. Nature 388, 769-773.
康世旭 (1996) 兩個吳郭魚麩胺酸受器，fGluR2□與fGluR2□的基因特性分析。清華大學輻射生物研究所博士論文。
吳怡宓(1998)吳郭魚麩胺酸受器cDNA之選殖及受器基因於發育不同時期 表現之研究。清華大學輻射生物研究所博士論文。
曾德旺(1998)魚類麩胺酸嵌合體受器 tGluR3□/1□之電生理特性研究。清華大學輻射生物研究所碩士論文。
范國賢(2000)魚類fGluR1□(i)及fGluR3□(i)麩胺酸嵌合體受器之電生理特性研究。清華大學生命科學所碩士論文。