臺灣博碩士論文加值系統

腦水腫是中風病患病理生成及致死性的主因。目前研究所知大腦各部位細胞內外水分運輸與一群水通道蛋白質(aquaporin, AQP)有關，是細胞膜上很特殊的蛋白質，只允許水通過，而不容許其他分子或離子通過，在腦中以AQP-4的表現最為顯著，然而AQP在腦水腫生成所扮演的角色目前尚未明確。胍丁胺(Agmatine)的角色已知是一種內生性clonidine取代物質，具有α2-腎上腺致效劑功能、imidazoline接受器及NMDA (N-methyl-D-aspartate)接受器的拮抗等功能。過去研究發現在不同腦創傷或腦缺血之動物模式中，Agmatine皆提供神經保護性功能，其機轉可能是透過佔據麩胺酸(Glutamate)作用在NMDA接受器的部位。至於Agmatine是否對於腦水腫具有治療效果目前仍未知。因此本實驗目的將利用中大腦動脈阻斷造成腦部缺血性損傷動物模式探討Agmatine治療對於aquaporin4表現之影響。
實驗將動物隨機分為三組：假手術組、腦中風合併生理食鹽水治療組及腦中風合併Agmatine治療組（100mg/ kg）。腦中風模式將採用4-0 nylon縫線前端利用熱原將頭部燒圓並圖上一層膠狀物，縫線由外頸動脈行經內頸動脈再往上約18-19mm處即可阻斷中大腦動脈之血流。當缺血達90分鐘後將縫線移除進行血液再灌流，並即刻給予腹膜內生理食鹽水或Agmatine治療，在再灌流三天後取出腦組織進行免疫組織化學染色法，用來分析AQP-4， iNOS (誘導型一氧化氮生成酵素)的表現，並利用雙重免疫組織化學染色法偵測具有AQP4表現的細胞型態。利用傾斜板測試實驗動物在傾斜板上可捉穩的角度來探討Agmatine治療的效果。此外本實驗也透過微透析技術、三苯基四唑化氯(2,3,5-Triphenyl Tetrazolium Chloride : TTC)染色及免疫螢光染色的技術探討當缺血發生時腦部生化代謝及細胞膜完整性之變化，以期探討Agmatine治療後之保護機轉。
實驗結果顯示：在腦缺血過程中，腦中風合併生理食鹽水治療組有顯著細胞興奮性毒性(Glutamate濃度由10.4±0.6μmol/L增加至75.2±1.0μmol/L)、無氧代謝(Lactate/Pyruvate ratio由47.4±1.4增加至137.1±13.2)、及細胞膜缺損(Glycerol由9.0±0.3μmol/L增加至37.2±2.6μmol/L)，在Agmatine治療組也有類似的結果(Glutamate濃度由11.1±2.0μmol/L增加至83.7±8.9μmol/L、Lactate/Pyruvate ratio由42.2±2.9增加至105.2±22.4、Glycerol由9.3±0.7μmol/L增加至34.3±0.9μmol/L)。於再灌流三天後，腦中風合併生理食鹽水治療組與Agmatine治療組比較可見腦梗塞體積降低87% (由387±32 mm3減少至50±12mm3；P<0.01)。至於AQP4的表現如下：在受傷側的皮質區，於MCAo 72小時後AQP4表現的數量在生理食鹽水治療組與給予Agmatine治療的結果分別為139.25±25.2 及81±11.1(p<0.05)呈現出Agmatine能降低AQP4的表現。運動方面也有77.7%降低因腦缺血造成的運動缺損的效果。
Agmatine確實可以讓因腦梗塞後造成的運動缺損改善、減少腦中風後梗塞的範圍、並降低神經元及神經膠質細胞的細胞凋亡、減少神經膠質細胞增生所帶來的傷害，並透過減少AQP-4的表現達到減少細胞水腫的結果進而保護神經元細胞。

Cerebral edema contributes to morbidity and mortality in stroke. The regulation of water balance in the brain is crucial. A disruption in this equilibrium causes an increase in brain water content that significantly contributes to the pathophysiology of traumatic brain injury, hydrocephalus, and a variety of neurological disorders. The discovery of the aquaporin (AQP) family of membrane water channels has provided important new insights into the physiology and pathology of brain water homeostasis. A number of recent studies are described in the review that demonstrated the important role of AQP4 in brain water balance and cerebral edema. Agmatine is an endogenous clonidine-displacing substance, an agonist for the α-2-adrenergic and imidazoline receptors, and an antagonist at N-methyl-D-aspartate (NMDA) receptors. In the present study, we examined alterations in glial and neuronal cell responses to the reported neuroprotective action of agmatine against cerebral ischemia. Rats were randomly divided into three groups: sham operation group, middle cerebral artery occlusion (MCAo) with saline treatment group, and MCAo with agmatine (100 mg/kg body weight) treatment group. Adult Sprague-Dawley rats were given intraperitoneal injection of agmatine or saline immediately after 90 min occlusion of the middle cerebral artery. In all animals, regional cerebral blood flow (rCBF) were measured by laser-Doppler flowmetery with flexible probe fixed on the skull starting before onset of ischemia until 2 hours after reperfusion. Implanting an intracranial microdialysis probe was assessed the markers of cerebral ischemia and cellular injury (including glycerol, glutamate and lactate/pyruvate ratio) in brain. Focal cerebral ischemia (for 90 minutes) was induced by MCAo by introducing a 4-0 monofilament nylon suture, whose tip have been rounded by heating near a flame and coated with poly-L-lysine, were introduced from the carotid bifurcation into the internal carotid artery until a mild resistance were felt (18 to 19 mm), thereby occluding the origin of the MCA. We used immunohistochemistry and immunofluorescence staining to determine the levels of AQP-4, and iNOS at different time points (1hr, 3hrs, 48hr, and 72hours) after transient MCAo. Brain swelling were quantitated in dry/ wet ratio at the level of the ipsilateral hemisphere. The maximum grip angle in an inclined plane was measured to determine motor performance whereas the percent of maximal possible effect was used to measure blockade of proprioception. The triphenyltetrazolium chloride (TTC) staining procedures were used for cerebral infarction assay. Our results revealed that, after the onset of MCAo, the neuronal ischemia/ damage markers were all significantly increased. Similarly, the protein expression of iNOS and AQP-4, were all significantly elevated in the cortex, hippocampus, and striatum of rat brain after at 3days after reperfusion, and result in neuronal apoptosis, gliosis and locomotor dysfuction. Systemic treatment with agmatine significantly enhanced survival of glial cells at 3 days after reperfusion of the MCA, and the preservation of these glial cells in the ischemic brain corresponded with a markedly reduced area of infarction as well as increased neuronal survival. The ischemia-induced locomotor and proprioception deficits were partially ameliorated in agmatine-treated animals evaluated at 3 days after the reperfusion of the MCA. Immunohistological assays further demonstrated that agmatine treatment significantly reduced the overexpression of the iNOS and AQP-4 of the ischemic brains. These results suggest that agmatine may cause attenuation of cerebral infarction as well as motor deficits by enhancing glial cell and neuronal survival.

中文摘要 iv
英文摘要 vi
目次 viii
圖目次 x

第一章 緒論 1
第一節 腦梗塞流行病學 1
第二節 腦缺血後腦部的變化 1
一 血流改變 1
二 葡萄糖及氧氣供應缺乏 2
三 粒線體破壞 2
四 穀氨酸鹽增加 3
五 一氧化氮生成酵素的表現 4
第三節 水通道蛋白與腦缺血的關係 5
一 水通道蛋白 5
二 腦內水通道蛋白的表現 6
三 腦內水的平衡 7
四 水通道與腦水腫 7
五 AQP4與腦水腫的關係 9
第四節 胍丁胺與腦缺血 10
一 胍丁胺的生物合成及代謝 10
二 Agmatine在腦內的分布及釋放 11
三 Agmatine的生物活性 11
四 Agmatine與NOS 12
第二章 實驗目的 14
第三章 實驗材料與方法 16
第一節 實驗動物 16
第二節 實驗方法 16
一 實驗設計 16
二 腦缺血及再灌流的誘發 18
三 生理參數監測 20
四 微透析收集細胞外液 21
五 腦組織缺血定性染色分析 21
六 梗塞體積之計算 23
七 免疫化學及螢光染色法 23
八 細胞凋亡之分析(TUNEL) 26
九 神經元凋亡分析( NeuN + TUNEL) 27
十 腦內水含量測量 27
十一 運動功能測試 27
十二 細胞計數 28
十三 統計分析 28
第四章 實驗流程與架構 29
第五章 研究結果 30
第一節 MCAo造成平均動脈壓上升及腦血流下降 30
第二節 Agmatine可降低細胞外液中的Glutamate、Glycerol、Lactate/Pyruvate ratio 30
第三節 Agmatine明顯降低梗塞範圍 31
第四節 Agmatine明顯的阻斷因缺血造的AQP4過度表現 31
第五節 Agmatine明顯的抑制了因缺血後造成的細胞凋亡 32
第六節 Agmatine明顯的改善因腦缺血所造成的神經膠細胞增生(Gliosis) 32
第七節 Agmatine明顯的改變因缺血所造成的iNOS過度表現 33
第八節 Agmatine明顯減少因腦缺血所增加的腦內水含量 33
第九節 Agmatine明顯改善運動功能的缺損 34
第六章 結果討論 72
第一節 Agmatine可保護神經膠質細胞免於缺血的傷害 72
第二節 Agmatine透過抑制NO的產生達到保護神經的效果 74
第三節 Agmatine可降低AQP4的表現，降低因腦缺血造成的腦水腫 74
第七章 結論 76
第八章 參考文獻 77
第九章 未來工作 82

1.Chiu, L., et al., Analysis of costs borne by families of patients hospitalized for stroke. Zhonghua Yi Xue Za Zhi (Taipei), 1998. 61(5): p. 267-75.
2.Chang, C.C. and Chen, C.J., Secular trend of mortality from cerebral infarction and cerebral hemorrhage in Taiwan, 1974-1988. Stroke, 1993. 24(2): p. 212-8.
3.Lipton, P., Ischemic cell death in brain neurons. Physiol Rev, 1999. 79(4): p. 1431-568.
4.Duverger, D. and E.T. MacKenzie, The quantification of cerebral infarction following focal ischemia in the rat: influence of strain, arterial pressure, blood glucose concentration, and age. J Cereb Blood Flow Metab, 1988. 8(4): p. 449-61.
5.Nedergaard, M., A. Gjedde, and N.H. Diemer, Focal ischemia of the rat brain: autoradiographic determination of cerebral glucose utilization, glucose content, and blood flow. J Cereb Blood Flow Metab, 1986. 6(4): p. 414-24.
6.Zhao, W., L. Belayev, and M.D. Ginsberg, Transient middle cerebral artery occlusion by intraluminal suture: II. Neurological deficits, and pixel-based correlation of histopathology with local blood flow and glucose utilization. J Cereb Blood Flow Metab, 1997. 17(12): p. 1281-90.
7.Goldberg, M.P. and D.W. Choi, Combined oxygen and glucose deprivation in cortical cell culture: calcium-dependent and calcium-independent mechanisms of neuronal injury. J Neurosci, 1993. 13(8): p. 3510-24.
8.Hertz, L., Bioenergetics of cerebral ischemia: a cellular perspective. Neuropharmacology, 2008. 55(3): p. 289-309.
9.Schurr, A., Lactate, glucose and energy metabolism in the ischemic brain (Review). Int J Mol Med, 2002. 10(2): p. 131-6.
10.Racay, P., et al., Ischemia-Induced Mitochondrial Apoptosis is Significantly Attenuated by Ischemic Preconditioning. Cell Mol Neurobiol, 2009.
11.Kluck, R.M., et al., The release of cytochrome c from mitochondria: a primary site for Bcl-2 regulation of apoptosis. Science, 1997. 275(5303): p. 1132-6.
12.Kroemer, G., B. Dallaporta, and M. Resche-Rigon, The mitochondrial death/life regulator in apoptosis and necrosis. Annu Rev Physiol, 1998. 60: p. 619-42.
13.Yang, J., et al., Prevention of apoptosis by Bcl-2: release of cytochrome c from mitochondria blocked. Science, 1997. 275(5303): p. 1129-32.
14.McBride, H.M., M. Neuspiel, and S. Wasiak, Mitochondria: more than just a powerhouse. Curr Biol, 2006. 16(14): p. R551-60.
15.Lyden, P. and N.G. Wahlgren, Mechanisms of action of neuroprotectants in stroke. J Stroke Cerebrovasc Dis, 2000. 9(6 Pt 2): p. 9-14.
16.Camacho, A. and L. Massieu, Role of glutamate transporters in the clearance and release of glutamate during ischemia and its relation to neuronal death. Arch Med Res, 2006. 37(1): p. 11-8.
17.Benveniste, H., et al., Elevation of the extracellular concentrations of glutamate and aspartate in rat hippocampus during transient cerebral ischemia monitored by intracerebral microdialysis. J Neurochem, 1984. 43(5): p. 1369-74.
18.Takagi, K., et al., Changes in amino acid neurotransmitters and cerebral blood flow in the ischemic penumbral region following middle cerebral artery occlusion in the rat: correlation with histopathology. J Cereb Blood Flow Metab, 1993. 13(4): p. 575-85.
19.Simon, R.P., et al., Blockade of N-methyl-D-aspartate receptors may protect against ischemic damage in the brain. Science, 1984. 226(4676): p. 850-2.
20.Wahl, F., et al., Extracellular glutamate during focal cerebral ischaemia in rats: time course and calcium dependency. J Neurochem, 1994. 63(3): p. 1003-11.
21.Mitani, A. and K. Kataoka, Critical levels of extracellular glutamate mediating gerbil hippocampal delayed neuronal death during hypothermia: brain microdialysis study. Neuroscience, 1991. 42(3): p. 661-70.
22.Baker, A.J., et al., Changes in extracellular concentrations of glutamate, aspartate, glycine, dopamine, serotonin, and dopamine metabolites after transient global ischemia in the rabbit brain. J Neurochem, 1991. 57(4): p. 1370-9.
23.Miyashita, K., et al., An adenosine uptake blocker, propentofylline, reduces glutamate release in gerbil hippocampus following transient forebrain ischemia. Neurochem Res, 1992. 17(2): p. 147-50.
24.Pellegrini-Giampietro, D.E., et al., Excitatory amino acid release and free radical formation may cooperate in the genesis of ischemia-induced neuronal damage. J Neurosci, 1990. 10(3): p. 1035-41.
25.Cazevieille, C., et al., Superoxide and nitric oxide cooperation in hypoxia/reoxygenation-induced neuron injury. Free Radic Biol Med, 1993. 14(4): p. 389-95.
26.Samdani, A.F., T.M. Dawson, and V.L. Dawson, Nitric oxide synthase in models of focal ischemia. Stroke, 1997. 28(6): p. 1283-8.
27.Busse, R. and A. Mulsch, Calcium-dependent nitric oxide synthesis in endothelial cytosol is mediated by calmodulin. FEBS Lett, 1990. 265(1-2): p. 133-6.
28.Lyons, C.R., G.J. Orloff, and J.M. Cunningham, Molecular cloning and functional expression of an inducible nitric oxide synthase from a murine macrophage cell line. J Biol Chem, 1992. 267(9): p. 6370-4.
29.Tait, M.J., et al., Water movements in the brain: role of aquaporins. Trends Neurosci, 2008. 31(1): p. 37-43.
30.Song, Y., N. Sonawane, and A.S. Verkman, Localization of aquaporin-5 in sweat glands and functional analysis using knockout mice. J Physiol, 2002. 541(Pt 2): p. 561-8.
31.Verkman, A.S., Roles of aquaporins in kidney revealed by transgenic mice. Semin Nephrol, 2006. 26(3): p. 200-8.
32.Oshio, K., et al., Reduced cerebrospinal fluid production and intracranial pressure in mice lacking choroid plexus water channel Aquaporin-1. FASEB J, 2005. 19(1): p. 76-8.
33.Longatti, P., et al., Aquaporin(s) expression in choroid plexus tumours. Pediatr Neurosurg, 2006. 42(4): p. 228-33.
34.Nielsen, S., et al., Distribution of the aquaporin CHIP in secretory and resorptive epithelia and capillary endothelia. Proc Natl Acad Sci U S A, 1993. 90(15): p. 7275-9.
35.Nielsen, S., et al., Specialized membrane domains for water transport in glial cells: high-resolution immunogold cytochemistry of aquaporin-4 in rat brain. J Neurosci, 1997. 17(1): p. 171-80.
36.Rash, J.E., et al., Direct immunogold labeling of aquaporin-4 in square arrays of astrocyte and ependymocyte plasma membranes in rat brain and spinal cord. Proc Natl Acad Sci U S A, 1998. 95(20): p. 11981-6.
37.Chen, C.H., et al., Effect of osmotherapy with hypertonic saline on regional cerebral edema following experimental stroke: a study utilizing magnetic resonance imaging. Neurocrit Care, 2007. 7(1): p. 92-100.
38.Meng, S., et al., Correspondence of AQP4 expression and hypoxic-ischaemic brain oedema monitored by magnetic resonance imaging in the immature and juvenile rat. Eur J Neurosci, 2004. 19(8): p. 2261-9.
39.Sun, M.C., et al., Regulation of aquaporin-4 in a traumatic brain injury model in rats. J Neurosurg, 2003. 98(3): p. 565-9.
40.Auguste, K.I., et al., Greatly impaired migration of implanted aquaporin-4-deficient astroglial cells in mouse brain toward a site of injury. FASEB J, 2007. 21(1): p. 108-16.
41.Saadoun, S., et al., Involvement of aquaporin-4 in astroglial cell migration and glial scar formation. J Cell Sci, 2005. 118(Pt 24): p. 5691-8.
42.Badaut, J. and L. Regli, Distribution and possible roles of aquaporin 9 in the brain. Neuroscience, 2004. 129(4): p. 971-81.
43.Amiry-Moghaddam, M., et al., Brain mitochondria contain aquaporin water channels: evidence for the expression of a short AQP9 isoform in the inner mitochondrial membrane. FASEB J, 2005. 19(11): p. 1459-67.
44.Frydenlund, D.S., et al., Temporary loss of perivascular aquaporin-4 in neocortex after transient middle cerebral artery occlusion in mice. Proc Natl Acad Sci U S A, 2006. 103(36): p. 13532-6.
45.Badaut, J., et al., Distribution of Aquaporin 9 in the adult rat brain: preferential expression in catecholaminergic neurons and in glial cells. Neuroscience, 2004. 128(1): p. 27-38.
46.Badaut, J., et al., Aquaporin 1 and aquaporin 4 expression in human brain after subarachnoid hemorrhage and in peritumoral tissue. Acta Neurochir Suppl, 2003. 86: p. 495-8.
47.Kiening, K.L., et al., Decreased hemispheric Aquaporin-4 is linked to evolving brain edema following controlled cortical impact injury in rats. Neurosci Lett, 2002. 324(2): p. 105-8.
48.Ke, C., et al., Heterogeneous responses of aquaporin-4 in oedema formation in a replicated severe traumatic brain injury model in rats. Neurosci Lett, 2001. 301(1): p. 21-4.
49.Taniguchi, M., et al., Induction of aquaporin-4 water channel mRNA after focal cerebral ischemia in rat. Brain Res Mol Brain Res, 2000. 78(1-2): p. 131-7.
50.Guerin, C.F., L. Regli, and J. Badaut, [Roles of aquaporins in the brain]. Med Sci (Paris), 2005. 21(8-9): p. 747-52.
51.Oshio, K., et al., Aquaporin-1 deletion reduces osmotic water permeability and cerebrospinal fluid production. Acta Neurochir Suppl, 2003. 86: p. 525-8.
52.Manley, G.T., et al., Aquaporin-4 deletion in mice reduces brain edema after acute water intoxication and ischemic stroke. Nat Med, 2000. 6(2): p. 159-63.
53.Papadopoulos, M.C. and A.S. Verkman, Aquaporin-4 gene disruption in mice reduces brain swelling and mortality in pneumococcal meningitis. J Biol Chem, 2005. 280(14): p. 13906-12.
54.Papadopoulos, M.C., et al., Aquaporin-4 facilitates reabsorption of excess fluid in vasogenic brain edema. FASEB J, 2004. 18(11): p. 1291-3.
55.Yang, X.C. and D.J. Reis, Agmatine selectively blocks the N-methyl-D-aspartate subclass of glutamate receptor channels in rat hippocampal neurons. J Pharmacol Exp Ther, 1999. 288(2): p. 544-9.
56.Halaris, A. and J. Plietz, Agmatine : metabolic pathway and spectrum of activity in brain. CNS Drugs, 2007. 21(11): p. 885-900.
57.Reis, D.J. and S. Regunathan, Is agmatine a novel neurotransmitter in brain? Trends Pharmacol Sci, 2000. 21(5): p. 187-93.
58.Li, G., et al., Agmatine: an endogenous clonidine-displacing substance in the brain. Science, 1994. 263(5149): p. 966-9.
59.Otake, K., et al., Regional localization of agmatine in the rat brain: an immunocytochemical study. Brain Res, 1998. 787(1): p. 1-14.
60.Reis, D.J., X.C. Yang, and T.A. Milner, Agmatine containing axon terminals in rat hippocampus form synapses on pyramidal cells. Neurosci Lett, 1998. 250(3): p. 185-8.
61.Piletz, J.E., D.N. Chikkala, and P. Ernsberger, Comparison of the properties of agmatine and endogenous clonidine-displacing substance at imidazoline and alpha-2 adrenergic receptors. J Pharmacol Exp Ther, 1995. 272(2): p. 581-7.
62.Reynolds, I.J., Arcaine uncovers dual interactions of polyamines with the N-methyl-D-aspartate receptor. J Pharmacol Exp Ther, 1990. 255(3): p. 1001-7.
63.Choi, D.W., J.Y. Koh, and S. Peters, Pharmacology of glutamate neurotoxicity in cortical cell culture: attenuation by NMDA antagonists. J Neurosci, 1988. 8(1): p. 185-96.
64.Auguet, M., et al., Selective inhibition of inducible nitric oxide synthase by agmatine. Jpn J Pharmacol, 1995. 69(3): p. 285-7.
65.Galea, E., et al., Inhibition of mammalian nitric oxide synthases by agmatine, an endogenous polyamine formed by decarboxylation of arginine. Biochem J, 1996. 316 ( Pt 1): p. 247-9.
66.Kim, J.H., et al., Agmatine reduces infarct area in a mouse model of transient focal cerebral ischemia and protects cultured neurons from ischemia-like injury. Exp Neurol, 2004. 189(1): p. 122-30.
67.Feng, Y., J.E. Piletz, and M.H. Leblanc, Agmatine suppresses nitric oxide production and attenuates hypoxic-ischemic brain injury in neonatal rats. Pediatr Res, 2002. 52(4): p. 606-11.
68.Gilad, G.M. and V.H. Gilad, Accelerated functional recovery and neuroprotection by agmatine after spinal cord ischemia in rats. Neurosci Lett, 2000. 296(2-3): p. 97-100.
69.Gilad, G.M., et al., Agmatine treatment is neuroprotective in rodent brain injury models. Life Sci, 1996. 58(2): p. PL 41-6.
70.Yu, C.G., et al., Agmatine improves locomotor function and reduces tissue damage following spinal cord injury. Neuroreport, 2000. 11(14): p. 3203-7.
71.Olmos, G., et al., Protection by imidazol(ine) drugs and agmatine of glutamate-induced neurotoxicity in cultured cerebellar granule cells through blockade of NMDA receptor. Br J Pharmacol, 1999. 127(6): p. 1317-26.
72.Longa, E.Z., et al., Reversible middle cerebral artery occlusion without craniectomy in rats. Stroke, 1989. 20(1): p. 84-91.
73.Gartshore, G., J. Patterson, and I.M. Macrae, Influence of ischemia and reperfusion on the course of brain tissue swelling and blood-brain barrier permeability in a rodent model of transient focal cerebral ischemia. Exp Neurol, 1997. 147(2): p. 353-60.
74.Wang, Y., et al., Glial cell line-derived neurotrophic factor protects against ischemia-induced injury in the cerebral cortex. J Neurosci, 1997. 17(11): p. 4341-8.
75.Mullen, R.J., C.R. Buck, and A.M. Smith, NeuN, a neuronal specific nuclear protein in vertebrates. Development, 1992. 116(1): p. 201-11.
76.Vakili, A., H. Kataoka, and N. Plesnila, Role of arginine vasopressin V1 and V2 receptors for brain damage after transient focal cerebral ischemia. J Cereb Blood Flow Metab, 2005. 25(8): p. 1012-9.
77.Chang, M.W., M.S. Young, and M.T. Lin, An inclined plane system with microcontroller to determine limb motor function of laboratory animals. J Neurosci Methods, 2008. 168(1): p. 186-94.
78.Davis, A.A. and S. Temple, A self-renewing multipotential stem cell in embryonic rat cerebral cortex. Nature, 1994. 372(6503): p. 263-6.
79.Regunathan, S., et al., Agmatine (decarboxylated arginine) is synthesized and stored in astrocytes. Neuroreport, 1995. 6(14): p. 1897-900.
80.Abe, K., Y. Abe, and H. Saito, Agmatine suppresses nitric oxide production in microglia. Brain Res, 2000. 872(1-2): p. 141-8.
81.Huang, Z., et al., Effects of cerebral ischemia in mice deficient in neuronal nitric oxide synthase. Science, 1994. 265(5180): p. 1883-5.
82.Morrissey, J.J. and S. Klahr, Agmatine activation of nitric oxide synthase in endothelial cells. Proc Assoc Am Physicians, 1997. 109(1): p. 51-7.
83.Iadecola, C., Bright and dark sides of nitric oxide in ischemic brain injury. Trends Neurosci, 1997. 20(3): p. 132-9.
84.Regunathan, S. and J.E. Piletz, Regulation of inducible nitric oxide synthase and agmatine synthesis in macrophages and astrocytes. Ann N Y Acad Sci, 2003. 1009: p. 20-9.
85.Frigeri, A., et al., Localization of MIWC and GLIP water channel homologs in neuromuscular, epithelial and glandular tissues. J Cell Sci, 1995. 108 ( Pt 9): p. 2993-3002.
86.Ma, T., et al., Generation and phenotype of a transgenic knockout mouse lacking the mercurial-insensitive water channel aquaporin-4. J Clin Invest, 1997. 100(5): p. 957-62.