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Shen N, Zhou L, Lai B, Li S. The Influence of Cochlear Implant-Based Electric Stimulation on the Electrophysiological Characteristics of Cultured Spiral Ganglion Neurons. Neural Plast 2020; 2020:3108490. [PMID: 32963515 PMCID: PMC7490630 DOI: 10.1155/2020/3108490] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2020] [Revised: 07/22/2020] [Accepted: 08/17/2020] [Indexed: 11/17/2022] Open
Abstract
Background Cochlear implant-based electrical stimulation may be an important reason to induce the residual hearing loss after cochlear implantation. In our previous study, we found that charge-balanced biphasic electrical stimulation inhibited the neurite growth of spiral ganglion neurons (SGNs) and decreased Schwann cell density in vitro. In this study, we want to know whether cochlear implant-based electrical stimulation can induce the change of electrical activity in cultured SGNs. Methods Spiral ganglion neuron electrical stimulation in vitro model is established using the devices delivering cochlear implant-based electrical stimulation. After 48 h treatment by 50 μA or 100 μA electrical stimulation, the action potential (AP) and voltage depended calcium current (I Ca) of SGNs are recorded using whole-cell electrophysiological method. Results The results show that the I Ca of SGNs is decreased significantly in 50 μA and 100 μA electrical stimulation groups. The reversal potential of I Ca is nearly +80 mV in control SGN, but the reversal potential decreases to +50 mV in 50 μA and 100 μA electrical stimulation groups. Interestingly, the AP amplitude, the AP latency, and the AP duration of SGNs have no statistically significant differences in all three groups. Conclusion Our study suggests cochlear implant-based electrical stimulation only significantly inhibit the I Ca of cultured SGNs but has no effect on the firing of AP, and the relation of I Ca inhibition and SGN damage induced by electrical stimulation and its mechanism needs to be further studied.
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Affiliation(s)
- Na Shen
- Department of Otolaryngology, Zhongshan Hospital, Fudan University, Shanghai, China
- ENT Institute and Department of Otolaryngology, Eye & ENT Hospital, Fudan University, Shanghai, China
| | - Lei Zhou
- Department of Otolaryngology, Zhongshan Hospital, Fudan University, Shanghai, China
| | - Bin Lai
- State Key Laboratory of Medical Neurobiology, Institutes of Brain Science, Fudan University, Shanghai 200032, China
| | - Shufeng Li
- ENT Institute and Department of Otolaryngology, Eye & ENT Hospital, Fudan University, Shanghai, China
- NHC Key Laboratory of Hearing Medicine (Fudan University), Shanghai, China
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Elmaci İ, Alturfan EE, Cengiz S, Ozpinar A, Altinoz MA. Neuroprotective and tumoricidal activities of cardiac glycosides. Could oleandrin be a new weapon against stroke and glioblastoma? Int J Neurosci 2018; 128:865-877. [DOI: 10.1080/00207454.2018.1435540] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Affiliation(s)
- İlhan Elmaci
- Department of Neurosurgery, Memorial Hospital, Istanbul, Turkey
| | | | - Salih Cengiz
- Department of Biochemistry, Institute of Forensic Medicine, Istanbul, Turkey
| | - Aysel Ozpinar
- Department of Medical Biochemistry, Acibadem University, Istanbul, Turkey
| | - Meric A. Altinoz
- Neuroacademy Group, Istanbul, Turkey
- Department of Psychiatry, Maastricht University, Holland
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Hu HH, Li SJ, Wang P, Yan HC, Cao X, Hou FQ, Fang YY, Zhu XH, Gao TM. An L-Type Calcium Channel Agonist, Bay K8644, Extends the Window of Intervention Against Ischemic Neuronal Injury. Mol Neurobiol 2012; 47:280-9. [DOI: 10.1007/s12035-012-8362-x] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2012] [Accepted: 10/01/2012] [Indexed: 01/04/2023]
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5
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Changes in the distribution of calbindin D28-k, parvalbumin, and calretinin in the hippocampus of the circling mouse. Brain Res 2012; 1437:58-68. [DOI: 10.1016/j.brainres.2011.12.009] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2011] [Revised: 11/18/2011] [Accepted: 12/04/2011] [Indexed: 01/29/2023]
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6
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Dunn DE, He DN, Yang P, Johansen M, Newman RA, Lo DC. In vitro and in vivo neuroprotective activity of the cardiac glycoside oleandrin from Nerium oleander in brain slice-based stroke models. J Neurochem 2011; 119:805-14. [PMID: 21950737 DOI: 10.1111/j.1471-4159.2011.07439.x] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The principal active constituent of the botanical drug candidate PBI-05204, a supercritical CO(2) extract of Nerium oleander, is the cardiac glycoside oleandrin. PBI-05204 shows potent anticancer activity and is currently in phase I clinical trial as a treatment for patients with solid tumors. We have previously shown that neriifolin, which is structurally related to oleandrin, provides robust neuroprotection in brain slice and whole animal models of ischemic injury. However, neriifolin itself is not a suitable drug development candidate and the FDA-approved cardiac glycoside digoxin does not cross the blood-brain barrier. We report here that both oleandrin as well as the full PBI-05204 extract can also provide significant neuroprotection to neural tissues damaged by oxygen and glucose deprivation as occurs in ischemic stroke. Critically, we show that the neuroprotective activity of PBI-05204 is maintained for several hours of delay of administration after oxygen and glucose deprivation treatment. We provide evidence that the neuroprotective activity of PBI-05204 is mediated through oleandrin and/or other cardiac glycoside constituents, but that additional, non-cardiac glycoside components of PBI-05204 may also contribute to the observed neuroprotective activity. Finally, we show directly that both oleandrin and the protective activity of PBI-05204 are blood brain barrier penetrant in a novel model for in vivo neuroprotection. Together, these findings suggest clinical potential for PBI-05204 in the treatment of ischemic stroke and prevention of associated neuronal death.
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Affiliation(s)
- Denise E Dunn
- Center for Drug Discovery and Department of Neurobiology, Duke University Medical Center, Durham, North Carolina 27514, USA
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7
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Cross JL, Meloni BP, Bakker AJ, Lee S, Knuckey NW. Modes of Neuronal Calcium Entry and Homeostasis following Cerebral Ischemia. Stroke Res Treat 2010; 2010:316862. [PMID: 21052549 PMCID: PMC2968719 DOI: 10.4061/2010/316862] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2010] [Accepted: 09/29/2010] [Indexed: 01/14/2023] Open
Abstract
One of the major instigators leading to neuronal cell death and brain damage following cerebral ischemia is calcium dysregulation. The neuron's inability to maintain calcium homeostasis is believed to be a result of increased calcium influx and impaired calcium extrusion across the plasma membrane. The need to better understand the cellular and biochemical mechanisms of calcium dysregulation contributing to neuronal loss following stroke/cerebral ischemia is essential for the development of new treatments in order to reduce ischemic brain injury. The aim of this paper is to provide a concise overview of the various calcium influx pathways in response to ischemia and how neuronal cells attempts to overcome this calcium overload.
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Affiliation(s)
- J L Cross
- Centre for Neuromuscular and Neurological Disorders, Australian Neuromuscular Research Institute, University of Western Australia, WA 6009, Australia
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8
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Chao D, Xia Y. Ionic storm in hypoxic/ischemic stress: can opioid receptors subside it? Prog Neurobiol 2009; 90:439-70. [PMID: 20036308 DOI: 10.1016/j.pneurobio.2009.12.007] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2009] [Revised: 09/10/2009] [Accepted: 12/17/2009] [Indexed: 12/17/2022]
Abstract
Neurons in the mammalian central nervous system are extremely vulnerable to oxygen deprivation and blood supply insufficiency. Indeed, hypoxic/ischemic stress triggers multiple pathophysiological changes in the brain, forming the basis of hypoxic/ischemic encephalopathy. One of the initial and crucial events induced by hypoxia/ischemia is the disruption of ionic homeostasis characterized by enhanced K(+) efflux and Na(+)-, Ca(2+)- and Cl(-)-influx, which causes neuronal injury or even death. Recent data from our laboratory and those of others have shown that activation of opioid receptors, particularly delta-opioid receptors (DOR), is neuroprotective against hypoxic/ischemic insult. This protective mechanism may be one of the key factors that determine neuronal survival under hypoxic/ischemic condition. An important aspect of the DOR-mediated neuroprotection is its action against hypoxic/ischemic disruption of ionic homeostasis. Specially, DOR signal inhibits Na(+) influx through the membrane and reduces the increase in intracellular Ca(2+), thus decreasing the excessive leakage of intracellular K(+). Such protection is dependent on a PKC-dependent and PKA-independent signaling pathway. Furthermore, our novel exploration shows that DOR attenuates hypoxic/ischemic disruption of ionic homeostasis through the inhibitory regulation of Na(+) channels. In this review, we will first update current information regarding the process and features of hypoxic/ischemic disruption of ionic homeostasis and then discuss the opioid-mediated regulation of ionic homeostasis, especially in hypoxic/ischemic condition, and the underlying mechanisms.
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Affiliation(s)
- Dongman Chao
- Yale University School of Medicine, Department of Pediatrics, New Haven, CT 06520, USA
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9
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Vural M, Cosan TE, Ozbek Z, Cosan D, Sahin F, Burukoglu D. Digoxin may provide protection against vasospasm in subarachnoid haemorrhage. Acta Neurochir (Wien) 2009; 151:1135-41. [PMID: 19436949 DOI: 10.1007/s00701-009-0391-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2008] [Accepted: 04/21/2009] [Indexed: 12/11/2022]
Abstract
BACKGROUND Vasospasm is a significant reason for poor clinical outcome in subarachnoid haemorrhage (SAH). One of the possible causes of vasospasm is attributed to the inhibition of Na(+)/K(+)-ATPase and increased intracellular calcium. Although digoxin, a cardiac glycoside (CG), inhibits the Na(+)/K(+)-ATPase, diverse and contradictory biological actions of CGs have also been reported. This study aimed to investigate the effect of digoxin on an experimental vasospasm after subarachnoid haemorrhage (SAH) in rats. METHODS The rats used in the study were divided into normal, saline, SAH, and drug groups. A double-haemorrhage method was applied for the SAH groups. Normal saline or blood samples were injected into the cisterna magna. No surgical procedures were performed on the normal group. For the drug groups, daily digoxin was administered intraperitoneally after saline or blood injections. On days 3 and 7 after injections, the brains and basilar artery sections of all the groups were prepared for light-microscopic examination. The wall thickness and luminal area of the basilar artery were calculated by using medical imaging software. RESULTS Increased wall thickness and reduced vessel luminal area were conspicuously significant in the SAH groups which did not receive digoxin. In SAH groups after digoxin administration, the vessel wall thickness decreased, and no significant change was found in vessel wall thickness when compared with the normal and saline groups. The vessel luminal area was not reduced in SAH after digoxin administration. CONCLUSIONS These results suggest that digoxin administration in experimental SAH may have a beneficial effect on the protection against vasospasm. If further investigations support our results, the present study may offer a new insight into the treatment of SAH.
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Affiliation(s)
- Murat Vural
- Department of Neurosurgery, Medical Faculty, Eskisehir Osmangazi University, Dede Mah. Alp Konutlari, Alp-4, D-Blok, Daire-2, Eskisehir, Turkey
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10
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Li XM, Yang JM, Hu DH, Hou FQ, Zhao M, Zhu XH, Wang Y, Li JG, Hu P, Chen L, Qin LN, Gao TM. Contribution of downregulation of L-type calcium currents to delayed neuronal death in rat hippocampus after global cerebral ischemia and reperfusion. J Neurosci 2007; 27:5249-59. [PMID: 17494711 PMCID: PMC6672382 DOI: 10.1523/jneurosci.0802-07.2007] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Transient forebrain ischemia induces delayed, selective neuronal death in the CA1 region of the hippocampus. The underlying molecular mechanisms are as yet unclear, but it is known that activation of L-type Ca2+ channels specifically increases the expression of a group of genes required for neuronal survival. Accordingly, we examined temporal changes in L-type calcium-channel activity in CA1 and CA3 pyramidal neurons of rat hippocampus after transient forebrain ischemia by patch-clamp techniques. In vulnerable CA1 neurons, L-type Ca2+-channel activity was persistently downregulated after ischemic insult, whereas in invulnerable CA3 neurons, no change occurred. Downregulation of L-type calcium channels was partially caused by oxidation modulation in postischemic channels. Furthermore, L-type but neither N-type nor P/Q-type Ca2+-channel antagonists alone significantly inhibited the survival of cultured hippocampal neurons. In contrast, specific L-type calcium-channel agonist remarkably reduced neuronal cell death and restored the inhibited channels induced by nitric oxide donor. More importantly, L-type calcium-channel agonist applied after reoxygenation or reperfusion significantly decreased neuronal injury in in vitro oxygen-glucose deprivation ischemic model and in animals subjected to forebrain ischemia-reperfusion. Together, the present results suggest that ischemia-induced inhibition of L-type calcium currents may give rise to delayed death of neurons in the CA1 region, possibly via oxidation mechanisms. Our findings may lead to a new perspective on neuronal death after ischemic insult and suggest that a novel therapeutic approach, activation of L-type calcium channels, could be tested at late stages of reperfusion for stroke treatment.
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Affiliation(s)
- Xiao-Ming Li
- Department of Anatomy and Neurobiology, Southern Medical University, Guangzhou 510515, People's Republic of China
| | - Jian-Ming Yang
- Department of Anatomy and Neurobiology, Southern Medical University, Guangzhou 510515, People's Republic of China
| | - De-Hui Hu
- Department of Anatomy and Neurobiology, Southern Medical University, Guangzhou 510515, People's Republic of China
| | - Feng-Qing Hou
- Department of Anatomy and Neurobiology, Southern Medical University, Guangzhou 510515, People's Republic of China
| | - Miao Zhao
- Department of Anatomy and Neurobiology, Southern Medical University, Guangzhou 510515, People's Republic of China
| | - Xin-Hong Zhu
- Department of Anatomy and Neurobiology, Southern Medical University, Guangzhou 510515, People's Republic of China
| | - Ying Wang
- Department of Anatomy and Neurobiology, Southern Medical University, Guangzhou 510515, People's Republic of China
| | - Jian-Guo Li
- Department of Anatomy and Neurobiology, Southern Medical University, Guangzhou 510515, People's Republic of China
| | - Ping Hu
- Department of Anatomy and Neurobiology, Southern Medical University, Guangzhou 510515, People's Republic of China
| | - Liang Chen
- Department of Anatomy and Neurobiology, Southern Medical University, Guangzhou 510515, People's Republic of China
| | - Lu-Ning Qin
- Department of Anatomy and Neurobiology, Southern Medical University, Guangzhou 510515, People's Republic of China
| | - Tian-Ming Gao
- Department of Anatomy and Neurobiology, Southern Medical University, Guangzhou 510515, People's Republic of China
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11
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Pottorf WJ, Johanns TM, Derrington SM, Strehler EE, Enyedi A, Thayer SA. Glutamate-induced protease-mediated loss of plasma membrane Ca2+ pump activity in rat hippocampal neurons. J Neurochem 2006; 98:1646-56. [PMID: 16923173 PMCID: PMC3873837 DOI: 10.1111/j.1471-4159.2006.04063.x] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Ca2+ dysregulation is a hallmark of excitotoxicity, a process that underlies multiple neurodegenerative disorders. The plasma membrane Ca2+ ATPase (PMCA) plays a major role in clearing Ca2+ from the neuronal cytoplasm. Here, we show that the rate of PMCA-mediated Ca2+ efflux from rat hippocampal neurons decreased following treatment with an excitotoxic concentration of glutamate. PMCA-mediated Ca2+ extrusion following a brief train of action potentials exhibited an exponential decay with a mean time constant (tau) of 8.8 +/- 0.2 s. Four hours following the start of a 30 min treatment with 200 microm glutamate, a second population of cells emerged with slowed recovery kinetics (tau = 16.5 +/- 0.3 s). Confocal imaging of cells expressing an enhanced green fluorescent protein (EGFP)-PMCA4b fusion protein revealed that glutamate treatment internalized EGFP and that cells with reduced plasma membrane fluorescence had impaired Ca2+ clearance. Treatment with inhibitors of the Ca2+-activated protease calpain protected PMCA function and prevented EGFP-PMCA internalization. PMCA internalization was triggered by activation of NMDA receptors and was less pronounced for a non-toxic concentration of glutamate relative to one that produces excitotoxicity. PMCA isoform 2 also internalized following exposure to glutamate, although the Na+/K+ ATPase did not. These data suggest that glutamate exposure initiated protease-mediated internalization of PMCAs with a corresponding loss of function that may contribute to the Ca2+ dysregulation that accompanies excitotoxicity.
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Affiliation(s)
- William J Pottorf
- Department of Pharmacology, University of Minnesota Medical School, Minneapolis, Minnesota 55455, USA
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12
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Wang JKT, Portbury S, Thomas MB, Barney S, Ricca DJ, Morris DL, Warner DS, Lo DC. Cardiac glycosides provide neuroprotection against ischemic stroke: discovery by a brain slice-based compound screening platform. Proc Natl Acad Sci U S A 2006; 103:10461-10466. [PMID: 16793926 PMCID: PMC1481664 DOI: 10.1073/pnas.0600930103] [Citation(s) in RCA: 73] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
We report here the results of a chemical genetic screen using small molecules with known pharmacologies coupled with a cortical brain slice-based model for ischemic stroke. We identified a small-molecule compound not previously appreciated to have neuroprotective action in ischemic stroke, the cardiac glycoside neriifolin, and demonstrated that its properties in the brain slice assay included delayed therapeutic potential exceeding 6 h. Neriifolin is structurally related to the digitalis class of cardiac glycosides, and its putative target is the Na(+)/K(+)-ATPase. Other cardiac glycoside compounds tested also showed neuroprotective activity, although with lower apparent potencies. In subsequent whole-animal studies, we found that neriifolin provided significant neuroprotection in a neonatal model of hypoxia/ischemia and in a middle cerebral artery occlusion model of transient focal ischemia. The neuroprotective potential of Na(+)/K(+)-ATPase is of particular interest because of its known "druggability"; indeed, Food and Drug Administration-approved, small-molecule compounds such as digitoxin and digoxin have been in clinical usage for congestive heart failure and arrhythmias for several decades. Thus, an existing cardiac glycoside or closely related compound could provide an accelerated path toward clinical trial testing for ischemic stroke. Our findings underscore the important role that hypothesis-neutral, high-content, tissue-based screens can play in the identification of new candidate drugs and drug targets for the treatment of diseases for which validated therapeutic pathways are not currently available.
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Affiliation(s)
| | | | | | | | | | | | - David S Warner
- Multidisciplinary Neuroprotection Laboratories and Department of Anesthesiology, Duke University Medical Center, Durham, NC 27710; and
| | - Donald C Lo
- *Cogent Neuroscience, Inc., Durham, NC 27704;
- **Center for Drug Discovery and Department of Neurobiology, Duke University Medical Center, Durham, NC 27704
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Vigh L, Smith RG, Soós J, Engelhardt JI, Appel SH, Siklós L. Sublethal dose of 4-hydroxynonenal reduces intracellular calcium in surviving motor neurons in vivo. Acta Neuropathol 2005; 109:567-75. [PMID: 15933871 DOI: 10.1007/s00401-004-0977-1] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2004] [Revised: 12/13/2004] [Accepted: 12/13/2004] [Indexed: 11/29/2022]
Abstract
4-Hydroxynonenal (4-HNE), a major lipid peroxidation product, induces oxidative stress, acts as an autonomous effector of cell death in motor neuron hybrid cell cultures, and is elevated in the cerebrospinal fluid (CSF) of patients with amyotrophic lateral sclerosis (ALS). Elevation of the total intracellular calcium has also been demonstrated in motor axon terminals of ALS patients as well as in spinal motor neurons of animal models of familial and sporadic ALS. Since the association of intracellular calcium and oxidative stress has been suggested in ALS, the in vivo effect of intrathecally administered 4-HNE on the motor neuronal calcium level was examined in the spinal cord of rats. After 12 days of treatment, total intracellular calcium was assayed by electron microscopic histochemistry using the oxalate-pyroantimonate method. Morphology of spinal motor neurons was characterized by light and electron microscopy. In rats, 4-HNE treatment induced a mild impairment of gait, elevation of 4-HNE in the CSF, loss of spinal motor neurons, and reduction of total calcium in the surviving, structurally intact motor neurons. 4-HNE could only cause a lesion if glutathione synthesis was concomitantly inhibited in the animals. The results suggest that upstream components of the oxidative injury in relation to lipid peroxidation are necessary to compromise the glutathione system in ALS, allowing an increase of 4-HNE in the CSF, which further aggravates the primary oxidative lesion. The reduced intracellular calcium in the surviving motor neurons with no morphological features of degeneration may reflect an impaired ionic homeostasis, which may indicate a residual damage of an incomplete degenerative process.
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Affiliation(s)
- Lóránd Vigh
- Institute of Biophysics, Biological Research Center, P.O. Box 521, 6701, Szeged, Hungary
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14
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Rüttimann E, Vacher CM, Gassmann M, Kaupmann K, Van der Putten H, Bettler B. Altered hippocampal expression of calbindin-D-28k and calretinin in GABAB(1)-deficient mice. Biochem Pharmacol 2004; 68:1613-20. [PMID: 15451404 DOI: 10.1016/j.bcp.2004.07.019] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2004] [Accepted: 07/07/2004] [Indexed: 10/26/2022]
Abstract
Balb/c GABA(B(1))(-/-) mice develop complex epileptiform activity, including spontaneous and audiogenic generalized seizures, 6-8 weeks after birth. The neuronal systems involved in these epilepsies have not been identified yet. Because the hippocampus is critically involved in epileptiform activity, we now investigated whether this brain region exhibits seizure-related alterations. Using semi-quantitative immunohistochemistry, we studied the temporal and cellular hippocampal expression pattern of two seizure-sensitive calcium-binding proteins, calbindin-D-28k and calretinin, in GABA(B(1))(-/-) mice. One month after birth, before the onset of overt epileptiform activity, wild-type (WT) and GABA(B(1))(-/-) mice exhibit comparable expression profiles for the two calcium-binding proteins. Three months after birth, once the epileptic phenotype is established, we observe clear alterations in the expression of calcium-binding proteins in the dentate gyrus area. GABA(B(1))(-/-) mice exhibit a 50% decline in the staining intensity of calbindin-D-28k expressing neurons and a 70% increase in the number of calretinin-positive neurons when compared to WT littermates. Six months after birth, the down-regulation of calbindin-D-28k protein is even more pronounced, while the calretinin expression in GABA(B(1))(-/-) mice reverts to the pattern seen in WT littermates. Our data demonstrate that the absence of functional GABA(B) receptors causes epileptiform activity through a mechanism that crucially involves dentate gyrus granule cells, and that this pathological activity is accompanied by adaptive changes.
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Affiliation(s)
- Elisabeth Rüttimann
- Department of Clinical-Biological Sciences, Institute of Physiology, University of Basel, Klingelbergstrasse 50-70, CH-4056 Basel, Switzerland
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Xing H, Azimi-Zonooz A, Shuttleworth CW, Connor JA. Caffeine releasable stores of Ca2+ show depletion prior to the final steps in delayed CA1 neuronal death. J Neurophysiol 2004; 92:2960-7. [PMID: 15201305 DOI: 10.1152/jn.00015.2004] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
In addition to their role in signaling, Ca2+ ions in the endoplasmic reticulum also regulate important steps in protein processing and trafficking that are critical for normal cell function. Chronic depletion of Ca2+ in the endoplasmic reticulum has been shown to lead to cell degeneration and has been proposed as a mechanism underlying delayed neuronal death following ischemic insults to the CNS. Experiments here have assessed the relative content of ryanodine receptor-gated stores in CA1 neurons by measuring cytoplasmic Ca2+ increases induced by caffeine. These measurements were performed on CA1 neurons, in slice, from normal gerbils, and compared with responses from this same population of neurons 54-60 h after animals had undergone a standard ischemic insult: 5-min bilateral occlusion of the carotid arteries. The mean amplitude of responses in the postischemic population were less than one-third of those in control or sham-operated animals, and 35% of the neurons from postischemic animals showed very small responses that were approximately 10% of the control population mean. Refilling of these stores after caffeine challenges was also impaired in postischemic neurons. These observations are consistent with our earlier finding that voltage-gated influx is sharply reduced in postischemic in CA1 neurons and the hypothesis that the resulting depletion in endosomal Ca2+ is an important cause of delayed neuronal death.
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Affiliation(s)
- Hong Xing
- Department of Neurosciences, University of New Mexico School of Medicine, Albuquerque, NM 87131, USA
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Canzoniero LMT, Babcock DJ, Gottron FJ, Grabb MC, Manzerra P, Snider BJ, Choi DW. Raising intracellular calcium attenuates neuronal apoptosis triggered by staurosporine or oxygen-glucose deprivation in the presence of glutamate receptor blockade. Neurobiol Dis 2004; 15:520-8. [PMID: 15056459 DOI: 10.1016/j.nbd.2003.10.013] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2002] [Revised: 07/21/2003] [Accepted: 10/18/2003] [Indexed: 10/26/2022] Open
Abstract
The relationship between intracellular Ca(2+) ([Ca(2+)](i)) regulation and programmed cell death is not well-defined; both increases and decreases in [Ca(2+)](i) have been observed in cells undergoing apoptosis. We determined [Ca(2+)](i) in cultured murine cortical neurons undergoing apoptosis after exposure to staurosporine or following oxygen-glucose deprivation in the presence of glutamate receptor antagonists. Neuronal [Ca(2+)](i) was decreased 1-4 h after exposure to staurosporine (30 nM). A [Ca(2+)](i) decrease was also observed 1 h after the end of the oxygen-glucose deprivation period when MK-801 and 6-cyano-7-nitroquinoxaline-2,3-dione (CNQX) were added to the bathing medium during the deprivation period. A similar decrease in [Ca(2+)](i) produced by reducing extracellular Ca(2+) or chelating intracellular Ca(2+) was sufficient to induce neuronal apoptosis. Raising [Ca(2+)](i) either by activating voltage-sensitive Ca(2+) channels with (-) Bay K8644 or by application of low concentrations of kainate attenuated both staurosporine and oxygen-glucose deprivation-induced apoptosis.
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Affiliation(s)
- Lorella M T Canzoniero
- Center for the Study of Nervous System Injury and Department of Neurology, Washington University School of Medicine, St. Louis, MO 63110, USA
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Abstract
We examined mechanisms contributing to stimulus-evoked changes in NAD(P)H fluorescence as a marker of neuronal activation in area CA1 of murine hippocampal slices. Three types of stimuli (electrical, glutamate iontophoresis, bath-applied kainate) produced biphasic fluorescence changes composed of an initial transient decrease ("initial component," 1-3%), followed by a longer-lasting transient increase ("overshoot," 3-8%). These responses were matched by inverted biphasic flavin adenine dinucleotide (FAD) fluorescence transients, suggesting that these transients reflect mitochondrial function rather than optical artifacts. Both components of NAD(P)H transients were abolished by ionotropic glutamate receptor block, implicating postsynaptic neuronal activation as the primary event involved in generating the signals, and not presynaptic activity or reuptake of synaptically released glutamate. Spatial analysis of the evoked signals indicated that the peak of each component could arise in different locations in the slice, suggesting that there is not always obligatory coupling between the two components. The initial NAD(P)H response showed a strong temporal correspondence to intracellular Ca+ increases and mitochondrial depolarization. However, despite the fact that removal of extracellular Ca2+ abolished neuronal cytosolic Ca2+ transients to exogenous glutamate or kainate, this procedure did not reduce slice NAD(P)H responses evoked by either of these agonists, implying that mechanisms other than neuronal mitochondrial Ca2+ loading underlie slice NAD(P)H transients. These data show that, in contrast to previous proposals, slice NAD(P)H transients in mature slices do not reflect neuronal Ca2+ dynamics and demonstrate that these signals are sensitive indicators of both the spatial and temporal characteristics of postsynaptic neuronal activation in these preparations.
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18
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Ishihara R, Ide-Ektessabi A, Ikeda K, Mizuno Y, Fujisawa S, Takeuchi T, Ohta T. Investigation of cellular metallic elements in single neurons of human brain tissues. Neuroreport 2002; 13:1817-20. [PMID: 12395131 DOI: 10.1097/00001756-200210070-00026] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
The purpose of this report is to introduce the potential of synchrotron radiation X-ray fluorescence (SRXRF) spectroscopy, by describing the application of this method to mapping and quantification of metallic elements in neurons from brain tissues affected by Alzheimer's disease (AD). In this study, clear images of Fe, Zn and Ca within certain single neurons were obtained. There was a high degree of correlation between Zn and Ca in the groups of cells with lower and relatively higher levels of Ca. These results demonstrate that further investigation with larger numbers of neurons using SRXRF spectroscopy may contribute to advancing the knowledge of the mechanisms of metal-induced cell degeneration in human brain tissues, including those affected by AD.
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Affiliation(s)
- Ryoko Ishihara
- Department of Psycgiatry, Nagoya University Graduate School of Medicine, Japan.
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19
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Gorter JA, Borgdorff AJ, van Vliet EA, Lopes da Silva FH, Wadman WJ. Differential and long-lasting alterations of high-voltage activated calcium currents in CA1 and dentate granule neurons after status epilepticus. Eur J Neurosci 2002; 16:701-12. [PMID: 12270046 DOI: 10.1046/j.1460-9568.2002.02108.x] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The effects on high-voltage activated (HVA) calcium currents were examined in hippocampal CA1 cells and dentate gyrus (DG) granule neurons, 2 days (short-term; ST) and 2-3 months (long-term; LT) after electrically induced, limbic electrographic and behavioural seizures in rats. Whole-cell voltage-clamp recordings in dissociated CA1 neurons of LT rats showed a decrease in the sustained HVA calcium current amplitude and a faster inactivation of the current both in rats that had experienced a status epilepticus (post-SE rats) and those in which the stimulation did not lead to SE (non-SE rats). In CA1 neurons of LT-SE rats this resulted in a reduced Ca2+ entry through the HVA channels. Perforated-patch voltage-clamp recordings in dissociated DG granule neurons of LT-SE rats showed an increased sustained HVA current amplitude compared to controls and non-SE rats, leading to an increased Ca2+ entry via HVA calcium channels. Two days after SE, we observed an increased Ca2+ entry for a defined depolarization, although the change in HVA current amplitude and inactivation rate did not reach significance. We also observed a decrease in calbindin-D28k staining in DG post-SE neurons, but this change was not associated with a change in HVA current inactivation. The opposite changes in neuronal Ca2+ entry through HVA channels in CA1 vs. DG cells depended strongly on whether rats had experienced SE and later spontaneous seizure activity. These changes are likely to contribute to regionally different effects on local network excitability.
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Affiliation(s)
- Jan A Gorter
- Swammerdam Institute for Life Sciences, Section Neurobiology, University of Amsterdam, Kruislaan 320, 1098 SM, Amsterdam, The Netherlands.
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20
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Abstract
The overactivation of glutamate receptors is a major cause of Ca(2+) overload in cells, potentially leading to cell damage and death. There is an abundance of agents and mechanisms by which glutamate receptor activation can be prevented or modulated in order to control these effects. They include the well-established, competitive and non-competitive antagonists at the N-methyl-D-aspartate (NMDA) receptors and modulators of desensitisation of the alpha-amino-3-hydroxy-5-methyl-4-isoxazole-propionic acid (AMPA) receptors. More recently, it has emerged that some compounds can act selectively at different subunits of glutamate receptors, allowing a differential blockade of subtypes. It is also becoming clear that a number of endogenous compounds, including purines, can modify glutamate receptor sensitivity. The kynurenine pathway is an alternative but distinct pathway to the generation of glutamate receptor ligands. The products of tryptophan metabolism via the kynurenine pathway include both quinolinic acid, a selective agonist at NMDA receptors, and kynurenic acid, an antagonist at several glutamate receptor subtypes. The levels of these metabolites change as a result of the activation of inflammatory processes and immune-competent cells, and may have a significant impact on Ca(2+) fluxes and neuronal damage. Drugs which target some of these various sites and processes, or which change the balance between the excitotoxin quinolinic acid and the neuroprotective kynurenic acid, could also have potential as neuroprotective drugs.
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Affiliation(s)
- Trevor W Stone
- Institute of Biomedical and Life Sciences Division of Neuroscience and Biomed. System, West Medical Building, University of Glasgow, Glasgow G12 8QQ, UK.
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21
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Abstract
Alterations in the transmembrane gradients of several physiological ions may influence programmed cell death. In particular, recent data suggest that increases in intracellular calcium may either promote or inhibit apoptosis, depending on the level, timing and location, whereas loss of intracellular potassium promotes apoptosis.
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Affiliation(s)
- S P Yu
- Center for the Study of Nervous System Injury and Department of Neurology, Washington University School of Medicine, 660 South Euclid Avenue, Missouri 63110, St. Louis, USA.
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22
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Chung YH, Shin CM, Kim MJ, Shin DH, Yoo YB, Cha CI. Spatial and temporal distribution of N-type Ca(2+) channels in gerbil global cerebral ischemia. Brain Res 2001; 902:294-300. [PMID: 11384625 DOI: 10.1016/s0006-8993(01)02443-x] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
In the present study, we have investigated the spatial and temporal distribution of voltage-gated calcium channels in the gerbil model of global cerebral ischemia using immunohistochemistry. Distinct localizations of P-type (alpha(1A)), N-type (alpha(1B)), and L-type (alpha(1C) and alpha(1D)) Ca(2+) channels were observed in the hippocampus at days 1-5 after ischemic injury. However, increased expression of N-type Ca(2+) channels was detectable in brain regions vulnerable to ischemia only at days 2 and 3 after ischemic injury. The pyramidal cell bodies of CA1-3 areas and the granule cell bodies of the dentate gyrus were intensely stained at days 2 and 3 following ischemic injury. Transient changes in N-type Ca(2+) channel expression were also observed in the affected cerebral cortex and striatum at days 2 and 3 after ischemic injury. Although the present study has not addressed the multiple mechanisms contributing to the intracellular free Ca(2+) concentration ([Ca(2+)](i)) increase in the ischemic brain, the first demonstration of the transient increase in N-type Ca(2+) channels may prove useful for future investigations.
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Affiliation(s)
- Y H Chung
- Department of Anatomy, Seoul National University College of Medicine, 28 Yongon-Dong, Chongno-Gu, 110-799, Seoul, South Korea
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23
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24
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Bruehl C, Neumann-Haefelin T, Witte OW. Enhancement of whole cell calcium currents following transient MCAO. Brain Res 2000; 884:129-38. [PMID: 11082494 DOI: 10.1016/s0006-8993(00)02927-9] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Cerebral infarctions have been shown to cause widespread changes of neuronal excitability in non-infarcted tissue. Calcium currents are major determinants of neuronal behavior, and pathological modulation of Ca(2+)-channels is known to lead to altered excitability states in a variety of paradigms. In the present study we addressed the question to what extent whole cell calcium currents are altered after middle cerebral artery occlusion (MCAO) in both the ipsi- and contralateral sensory cortex. Transient middle cerebral artery occlusion was induced for 1 h in rats using the intraluminal thread model. After 7 or 28 days survival, whole cell patch clamp studies were carried out on freshly isolated neurons of the ipsi- and contralateral sensory cortex, and high voltage activated (HVA) calcium currents were examined. In lesioned animals, we found a significant increase of calcium current amplitude and maximal conductance in the sensory cortex contralateral to the infarcts. This was paralleled by a prominent positive shift of the potential of half-maximal activation (V(h,a)) in these cells. Changes were long-lasting and at least stable for the following 28 days. These alterations were present in animals with lesions of moderate size, but not in those with massive infarction, and only in the cortex contralateral to the lesion. Following cortical infarctions, changes of calcium current properties are selectively observed in neurons contralateral to the lesion. At the behavioral level, compensatory mechanisms involving the unaffected hemisphere may induce this alteration of calcium current properties.
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Affiliation(s)
- C Bruehl
- Heinrich-Heine-University, Department of Neurology, Geb.: 22.22/TVA, 40225, Duesseldorf, Germany.
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25
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Zipfel GJ, Babcock DJ, Lee JM, Choi DW. Neuronal apoptosis after CNS injury: the roles of glutamate and calcium. J Neurotrauma 2000; 17:857-69. [PMID: 11063053 DOI: 10.1089/neu.2000.17.857] [Citation(s) in RCA: 214] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
While a role has been well established for excitotoxic necrosis in the pathogenesis of traumatic or ischemic damage to the CNS, accumulating evidence now suggests that apoptosis may also be a prominent contributor. In this review we focus on the role of glutamate and attendant intracellular calcium influx in triggering or modifying excitotoxic necrosis and apoptosis, raising the possibility that calcium influx may affect these two death pathways in opposite directions. Incorporating consideration of both pathways will probably be needed to develop the most effective neuroprotective treatments for CNS injury.
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Affiliation(s)
- G J Zipfel
- Center for the Study of Nervous System Injury and Department of Neurology, Washington University School of Medicine, Saint Louis, Missouri 63110, USA
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26
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Shuttleworth CW, Greenwood AC, Connor JA. Ca2+ signaling in gerbil CA3 hippocampal neurons following transient in vivo ischemia. Neurosci Lett 2000; 286:75-8. [PMID: 10825640 DOI: 10.1016/s0304-3940(00)01094-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/16/2022]
Abstract
Using the gerbil model of post-ischemic neuron death in the hippocampal CA1 region, it was recently shown that there is a strong down-regulation of voltage-gated Ca2+ influx in neurons examined at 2 days after the ischemic insult (Connor, J.A., Razani-Boroujerdi, S., Greenwood, A.C., Cormier, R.J., Petrozzino, J.J. and Lin, R.C., Reduced voltage-dependent Ca2+ signaling in CA1 neurons after brief ischemia in gerbils, J. Neurophysiol., 81 (1999) 299-306). The aim of the present study was to determine whether a similar change occurs in pyramidal neurons of the CA3 region that are relatively resistant to transient ischemia. In vitro intracellular recordings and fluorometric Ca2+ measurements were made from CA3 neurons in coronal slices prepared from controls and 1 or 2 days following in vivo ischemia. In slices from control and post-ischemic animals, the electrophysiological properties of CA3 neurons were consistent with significant voltage-gated Ca2+ influx, leading to spike frequency adaptation. Quantitative results indicated no significant difference in Ca2+ transients evoked by action potential trains. This Ca2+ signaling was compared with responses in CA1 neurons from the same preparations, which showed substantially diminished Ca2+ influx at 2 days post-ischemia. These findings suggest that diminished Ca2+-signaling is not a general feature of pyramidal neurons following ischemia, but is characteristic of neurons destined to die.
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Affiliation(s)
- C W Shuttleworth
- Department of Neurosciences, University of New Mexico, School of Medicine, Albuquerque, NM 87131, USA.
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27
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Plaschke K, Weigand MA, Michel A, Martin E, Bardenheuer HJ. Permanent cerebral hypoperfusion: 'preconditioning-like' effects on rat energy metabolism towards acute systemic hypotension. Brain Res 2000; 858:363-70. [PMID: 10708688 DOI: 10.1016/s0006-8993(00)01950-8] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Chronic cerebrovascular disorders are often complicated by additional temporary ischaemic insults, resulting in substantial deterioration of brain energy metabolism. In the present study, chronic limitations of oxygen supply were induced in Wistar rats by 2 weeks of permanent bilateral common carotid artery occlusion (2-vo) to initiate a 'preconditioning-like' effect that protects rat brain energy metabolism against further acute systemic hypotension (15 min). Haemodynamic parameters, arterial blood gases and body temperature were monitored. Energy metabolites were determined in rat parietotemporal cerebral cortex: adenosine 5'-triphosphate (ATP), adenosine 5'-diphosphate (ADP), adenosine 5'-monophosphate (AMP), phosphocreatine (PCr), and adenosine by the high-pressure liquid chromatography (HPLC) technique and lactate spectrophotometrically. After 2 weeks, permanent 2-vo led to a significant decrease in the concentrations of cortical tissue ATP and PCr, from 3.06+/-0.48 to 2. 09+/-0.28 and from 4.27+/-0.63 to 3.35+/-0.41 micromol/g, respectively. These changes were associated with a two-fold increase in AMP and adenosine. Acute systemic hypotension alone (non-preconditioning) reduced ATP and PCr drastically, to 0.97+/-0. 51 and 1.76+/-1.23 micromol/g. Tissue concentrations of lactate, AMP, and adenosine were markedly increased, three- to five-fold, in 'non-preconditioned' brain tissue. In contrast, after 2 weeks of 2-vo acute hypotension did not significantly alter the cortical energy state any further. The effects of preconditioning on tissue ATP and PCr were most pronounced at 5 min and 48 h after reperfusion. In conclusion, permanent 2-vo seems to activate compensatory mechanisms, which effectively protect the rat's cortical energy metabolism against an additional ischaemic attack ('preconditioning-like' effect).
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Affiliation(s)
- K Plaschke
- Clinic of Anesthesiology, University of Heidelberg, Im Neuenheimer Feld 110, D-69120, Heidelberg, Germany
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28
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Connor JA, Cormier RJ. Cumulative effects of glutamate microstimulation on Ca(2+) responses of CA1 hippocampal pyramidal neurons in slice. J Neurophysiol 2000; 83:90-8. [PMID: 10634856 DOI: 10.1152/jn.2000.83.1.90] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Glutamate stimulation of hippocampal CA1 neurons in slice was delivered via iontophoresis from a microelectrode. Five pulses (approximately 5 muA, 10 s duration, repeated at 1 min intervals) were applied with the electrode tip positioned in the stratum radiatum near the dendrites of a neuron filled with the Ca(2+) indicator fura-2. A single stimulus set produced Ca(2+) elevations that ranged from several hundred nM to several microM and that, in all but a few neurons, recovered within 1 min of stimulus termination. Subsequent identical stimulation produced Ca(2+) elevations that outlasted the local glutamate elevations by several minutes as judged by response recoveries in neighboring cells or in other parts of the same neuron. These long responses ultimately recovered but persisted for up to 10 min and were most prominent in the mid and distal dendrites. Recovery was not observed for responses that spread to the soma. The elevated Ca(2+) levels were accompanied by membrane depolarization but did not appear to depend on the depolarization. High-resolution images demonstrated responsive areas that involved only a few mu(m) of dendrite. Our results confirm the previous general findings from isolated and cell culture neurons that glutamate stimulation, if carried beyond a certain range, results in long-lasting Ca(2+) elevation. The response characterized here in mature in situ neurons was significantly different in terms of time course and reversibility. We suggest that the extended Ca(2+) elevations might serve not only as a trigger for delayed neuron death but, where more spatially restricted, as a signal for local remodeling in dendrites.
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Affiliation(s)
- J A Connor
- Department of Neuroscience, University of New Mexico School of Medicine, Albuquerque, New Mexico 87131, USA
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29
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Abstract
Thrombolysis has become established as an acute treatment for human stroke. But despite multiple clinical trials, neuroprotective strategies have yet to be proved effective in humans. Here we discuss intrinsic tissue mechanisms of ischaemic brain injury, and present a perspective that broadening of therapeutic targeting beyond excitotoxicity and neuronal calcium overload will be desirable for developing the most effective neuroprotective therapies.
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Affiliation(s)
- J M Lee
- Center for the Study of Nervous System Injury and Department of Neurology, Washington University School of Medicine, Saint Louis, Missouri 63110, USA
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