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Pál B. On the functions of astrocyte-mediated neuronal slow inward currents. Neural Regen Res 2024; 19:2602-2612. [PMID: 38595279 PMCID: PMC11168512 DOI: 10.4103/nrr.nrr-d-23-01723] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2023] [Revised: 12/25/2023] [Accepted: 01/24/2024] [Indexed: 04/11/2024] Open
Abstract
Slow inward currents are known as neuronal excitatory currents mediated by glutamate release and activation of neuronal extrasynaptic N-methyl-D-aspartate receptors with the contribution of astrocytes. These events are significantly slower than the excitatory postsynaptic currents. Parameters of slow inward currents are determined by several factors including the mechanisms of astrocytic activation and glutamate release, as well as the diffusion pathways from the release site towards the extrasynaptic receptors. Astrocytes are stimulated by neuronal network activity, which in turn excite neurons, forming an astrocyte-neuron feedback loop. Mostly as a consequence of brain edema, astrocytic swelling can also induce slow inward currents under pathological conditions. There is a growing body of evidence on the roles of slow inward currents on a single neuron or local network level. These events often occur in synchrony on neurons located in the same astrocytic domain. Besides synchronization of neuronal excitability, slow inward currents also set synaptic strength via eliciting timing-dependent synaptic plasticity. In addition, slow inward currents are also subject to non-synaptic plasticity triggered by long-lasting stimulation of the excitatory inputs. Of note, there might be important region-specific differences in the roles and actions triggering slow inward currents. In greater networks, the pathophysiological roles of slow inward currents can be better understood than physiological ones. Slow inward currents are identified in the pathophysiological background of autism, as slow inward currents drive early hypersynchrony of the neural networks. Slow inward currents are significant contributors to paroxysmal depolarizational shifts/interictal spikes. These events are related to epilepsy, but also found in Alzheimer's disease, Parkinson's disease, and stroke, leading to the decline of cognitive functions. Events with features overlapping with slow inward currents (excitatory, N-methyl-D-aspartate-receptor mediated currents with astrocytic contribution) as ischemic currents and spreading depolarization also have a well-known pathophysiological role in worsening consequences of stroke, traumatic brain injury, or epilepsy. One might assume that slow inward currents occurring with low frequency under physiological conditions might contribute to synaptic plasticity and memory formation. However, to state this, more experimental evidence from greater neuronal networks or the level of the individual is needed. In this review, I aimed to summarize findings on slow inward currents and to speculate on the potential functions of it.
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Affiliation(s)
- Balázs Pál
- Department of Physiology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
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2
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Csemer A, Sokvári C, Maamrah B, Szabó L, Korpás K, Pocsai K, Pál B. Pharmacological Activation of Piezo1 Channels Enhances Astrocyte-Neuron Communication via NMDA Receptors in the Murine Neocortex. Int J Mol Sci 2024; 25:3994. [PMID: 38612801 PMCID: PMC11012114 DOI: 10.3390/ijms25073994] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2024] [Revised: 03/28/2024] [Accepted: 03/30/2024] [Indexed: 04/14/2024] Open
Abstract
The Piezo1 mechanosensitive ion channel is abundant on several elements of the central nervous system including astrocytes. It has been already demonstrated that activation of these channels is able to elicit calcium waves on astrocytes, which contributes to the release of gliotransmitters. Astrocyte- and N-methyl-D-aspartate (NMDA) receptor-dependent slow inward currents (SICs) are hallmarks of astrocyte-neuron communication. These currents are triggered by glutamate released as gliotransmitter, which in turn activates neuronal NMDA receptors responsible for this inward current having slower kinetics than any synaptic events. In this project, we aimed to investigate whether Piezo1 activation and inhibition is able to alter spontaneous SIC activity of murine neocortical pyramidal neurons. When the Piezo1 opener Yoda1 was applied, the SIC frequency and the charge transfer by these events in a minute time was significantly increased. These changes were prevented by treating the preparations with the NMDA receptor inhibitor D-AP5. Furthermore, Yoda1 did not alter the spontaneous EPSC frequency and amplitude when SICs were absent. The Piezo1 inhibitor Dooku1 effectively reverted the actions of Yoda1 and decreased the rise time of SICs when applied alone. In conclusion, activation of Piezo1 channels is able to alter astrocyte-neuron communication. Via enhancement of SIC activity, astrocytic Piezo1 channels have the capacity to determine neuronal excitability.
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Affiliation(s)
- Andrea Csemer
- Department of Physiology, Faculty of Medicine, University of Debrecen, H-4002 Debrecen, Hungary; (A.C.); (C.S.); (B.M.); (K.K.); (K.P.)
- Doctoral School of Molecular Medicine, University of Debrecen, H-4012 Debrecen, Hungary;
| | - Cintia Sokvári
- Department of Physiology, Faculty of Medicine, University of Debrecen, H-4002 Debrecen, Hungary; (A.C.); (C.S.); (B.M.); (K.K.); (K.P.)
- Doctoral School of Molecular Medicine, University of Debrecen, H-4012 Debrecen, Hungary;
| | - Baneen Maamrah
- Department of Physiology, Faculty of Medicine, University of Debrecen, H-4002 Debrecen, Hungary; (A.C.); (C.S.); (B.M.); (K.K.); (K.P.)
- Doctoral School of Molecular Medicine, University of Debrecen, H-4012 Debrecen, Hungary;
| | - László Szabó
- Doctoral School of Molecular Medicine, University of Debrecen, H-4012 Debrecen, Hungary;
- HUN-REN DE Cell Physiology Research Group, H-4032 Debrecen, Hungary
| | - Kristóf Korpás
- Department of Physiology, Faculty of Medicine, University of Debrecen, H-4002 Debrecen, Hungary; (A.C.); (C.S.); (B.M.); (K.K.); (K.P.)
- Doctoral School of Molecular Medicine, University of Debrecen, H-4012 Debrecen, Hungary;
| | - Krisztina Pocsai
- Department of Physiology, Faculty of Medicine, University of Debrecen, H-4002 Debrecen, Hungary; (A.C.); (C.S.); (B.M.); (K.K.); (K.P.)
| | - Balázs Pál
- Department of Physiology, Faculty of Medicine, University of Debrecen, H-4002 Debrecen, Hungary; (A.C.); (C.S.); (B.M.); (K.K.); (K.P.)
- Doctoral School of Molecular Medicine, University of Debrecen, H-4012 Debrecen, Hungary;
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Nakajima H, Okada T, Kawakita F, Oinaka H, Suzuki Y, Nampei M, Kitano Y, Nishikawa H, Fujimoto M, Miura Y, Yasuda R, Toma N, Suzuki H. Cilostazol May Improve Outcomes Even in Patients with Aneurysmal Subarachnoid Hemorrhage Aged 75 Years and Older: Multicenter Cohort Study and Propensity Score-Matched Analyses. World Neurosurg 2024; 181:e273-e290. [PMID: 37839574 DOI: 10.1016/j.wneu.2023.10.039] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2023] [Revised: 10/07/2023] [Accepted: 10/08/2023] [Indexed: 10/17/2023]
Abstract
BACKGROUND The opportunities to treat elderly patients with aneurysmal subarachnoid hemorrhage (aSAH) are increasing globally, but the outcome remains poor. This study seeks to investigate treatment-related factors that can modify functional outcomes in patients with aSAH aged ≥75 years. METHODS A total of 202 patients with aSAH aged ≥75 years prospectively enrolled in 9 primary stroke centers from 2013 to 2021 were retrospectively analyzed. Clinical variables including treatments for hydrocephalus, angiographic vasospasm, and delayed cerebral ischemia were compared between patients with good (modified Rankin Scale [mRS] score 0-2) and poor (mRS score 3-6) outcomes at 90 days from onset, followed by multivariate analyses to find independent outcome determinants. A modifiable treatment-related variable was evaluated after propensity score matching with adjustments for age, sex, pre-onset mRS score, aSAH severity, and treatment modality. RESULTS More than half of patients showed World Federation of Neurological Societies grades IV-V on admission. Univariate analyses showed that advanced age, worse pre-onset mRS score, more severe neurologic status on admission, higher modified Fisher grade on admission computed tomography scans, and acute and chronic hydrocephalus were associated with poor outcomes. In contrast, administration of a phosphodiesterase type III inhibitor, cilostazol, was associated with good outcomes in both univariate (P = 0.036) and multivariate analyses (adjusted odds ratio, 0.305; 95% confidence interval, 0.097-0.955; P = 0.042). Propensity score matching analyses showed that patients treated with cilostazol had better outcomes (P = 0.016) with fewer incidences of delayed cerebral infarction (P = 0.008). CONCLUSIONS Even in patients with aSAH aged ≥75 years, cilostazol administration may lead to better outcomes by suppressing the development of delayed cerebral infarction.
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Affiliation(s)
- Hideki Nakajima
- Department of Neurosurgery, Mie University Graduate School of Medicine, Tsu, Japan.
| | - Takeshi Okada
- Department of Neurosurgery, Mie University Graduate School of Medicine, Tsu, Japan
| | - Fumihiro Kawakita
- Department of Neurosurgery, Mie University Graduate School of Medicine, Tsu, Japan
| | - Hiroki Oinaka
- Department of Neurosurgery, Mie University Graduate School of Medicine, Tsu, Japan
| | - Yume Suzuki
- Department of Neurosurgery, Mie University Graduate School of Medicine, Tsu, Japan
| | - Mai Nampei
- Department of Neurosurgery, Mie University Graduate School of Medicine, Tsu, Japan
| | - Yotaro Kitano
- Department of Neurosurgery, Mie University Graduate School of Medicine, Tsu, Japan
| | - Hirofumi Nishikawa
- Department of Neurosurgery, Mie University Graduate School of Medicine, Tsu, Japan
| | - Masashi Fujimoto
- Department of Neurosurgery, Mie University Graduate School of Medicine, Tsu, Japan
| | - Yoichi Miura
- Department of Neurosurgery, Mie University Graduate School of Medicine, Tsu, Japan
| | - Ryuta Yasuda
- Department of Neurosurgery, Mie University Graduate School of Medicine, Tsu, Japan
| | - Naoki Toma
- Department of Neurosurgery, Mie University Graduate School of Medicine, Tsu, Japan
| | - Hidenori Suzuki
- Department of Neurosurgery, Mie University Graduate School of Medicine, Tsu, Japan
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Csemer A, Kovács A, Maamrah B, Pocsai K, Korpás K, Klekner Á, Szücs P, Nánási PP, Pál B. Astrocyte- and NMDA receptor-dependent slow inward currents differently contribute to synaptic plasticity in an age-dependent manner in mouse and human neocortex. Aging Cell 2023; 22:e13939. [PMID: 37489544 PMCID: PMC10497838 DOI: 10.1111/acel.13939] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2022] [Revised: 07/12/2023] [Accepted: 07/14/2023] [Indexed: 07/26/2023] Open
Abstract
Slow inward currents (SICs) are known as excitatory events of neurons elicited by astrocytic glutamate via activation of extrasynaptic NMDA receptors. By using slice electrophysiology, we tried to provide evidence that SICs can elicit synaptic plasticity. Age dependence of SICs and their impact on synaptic plasticity was also investigated in both on murine and human cortical slices. It was found that SICs can induce a moderate synaptic plasticity, with features similar to spike timing-dependent plasticity. Overall SIC activity showed a clear decline with aging in humans and completely disappeared above a cutoff age. In conclusion, while SICs contribute to a form of astrocyte-dependent synaptic plasticity both in mice and humans, this plasticity is differentially affected by aging. Thus, SICs are likely to play an important role in age-dependent physiological and pathological alterations of synaptic plasticity.
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Affiliation(s)
- Andrea Csemer
- Department of Physiology, Faculty of MedicineUniversity of DebrecenDebrecenHungary
- Doctoral School of Molecular MedicineUniversity of DebrecenDebrecenHungary
| | - Adrienn Kovács
- Department of Physiology, Faculty of MedicineUniversity of DebrecenDebrecenHungary
| | - Baneen Maamrah
- Department of Physiology, Faculty of MedicineUniversity of DebrecenDebrecenHungary
- Doctoral School of Molecular MedicineUniversity of DebrecenDebrecenHungary
| | - Krisztina Pocsai
- Department of Physiology, Faculty of MedicineUniversity of DebrecenDebrecenHungary
| | - Kristóf Korpás
- Department of Physiology, Faculty of MedicineUniversity of DebrecenDebrecenHungary
| | - Álmos Klekner
- Department of Neurosurgery, Clinical CentreUniversity of DebrecenDebrecenHungary
| | - Péter Szücs
- Department of Anatomy, Histology and Embryology, Faculty of MedicineUniversity of DebrecenDebrecenHungary
| | - Péter P. Nánási
- Department of Physiology, Faculty of MedicineUniversity of DebrecenDebrecenHungary
- Department of Dental Physiology and Pharmacology, Faculty of DentistryUniversity of DebrecenDebrecenHungary
| | - Balázs Pál
- Department of Physiology, Faculty of MedicineUniversity of DebrecenDebrecenHungary
- Doctoral School of Molecular MedicineUniversity of DebrecenDebrecenHungary
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Mehra A, Gomez F, Bischof H, Diedrich D, Laudanski K. Cortical Spreading Depolarization and Delayed Cerebral Ischemia; Rethinking Secondary Neurological Injury in Subarachnoid Hemorrhage. Int J Mol Sci 2023; 24:9883. [PMID: 37373029 DOI: 10.3390/ijms24129883] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2023] [Revised: 05/15/2023] [Accepted: 05/23/2023] [Indexed: 06/29/2023] Open
Abstract
Poor outcomes in Subarachnoid Hemorrhage (SAH) are in part due to a unique form of secondary neurological injury known as Delayed Cerebral Ischemia (DCI). DCI is characterized by new neurological insults that continue to occur beyond 72 h after the onset of the hemorrhage. Historically, it was thought to be a consequence of hypoperfusion in the setting of vasospasm. However, DCI was found to occur even in the absence of radiographic evidence of vasospasm. More recent evidence indicates that catastrophic ionic disruptions known as Cortical Spreading Depolarizations (CSD) may be the culprits of DCI. CSDs occur in otherwise healthy brain tissue even without demonstrable vasospasm. Furthermore, CSDs often trigger a complex interplay of neuroinflammation, microthrombi formation, and vasoconstriction. CSDs may therefore represent measurable and modifiable prognostic factors in the prevention and treatment of DCI. Although Ketamine and Nimodipine have shown promise in the treatment and prevention of CSDs in SAH, further research is needed to determine the therapeutic potential of these as well as other agents.
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Affiliation(s)
- Ashir Mehra
- Department of Neurology, University of Missouri, Columbia, MO 65212, USA
| | - Francisco Gomez
- Department of Neurology, University of Missouri, Columbia, MO 65212, USA
| | - Holly Bischof
- Penn Presbyterian Medical Center, Philadelphia, PA 19104, USA
| | - Daniel Diedrich
- Department of Anesthesiology and Perioperative Care, Mayo Clinic, Rochester, MN 55905, USA
| | - Krzysztof Laudanski
- Department of Anesthesiology and Perioperative Care, Mayo Clinic, Rochester, MN 55905, USA
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Gainutdinov A, Juzekaeva E, Mukhtarov M, Khazipov R. Anoxic spreading depolarization in the neonatal rat cortex in vitro. Front Cell Neurosci 2023; 17:1106268. [PMID: 36970422 PMCID: PMC10034194 DOI: 10.3389/fncel.2023.1106268] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2022] [Accepted: 02/16/2023] [Indexed: 03/11/2023] Open
Abstract
Anoxic spreading depolarization (aSD) is a hallmark of ischemic injury in the cerebral cortex. In adults, aSD is associated with rapid and nearly complete neuronal depolarization and loss of neuronal functions. While ischemia also evokes aSD in the immature cortex, developmental aspects of neuronal behavior during aSD remain largely unknown. Here, using oxygen-glucose deprivation (OGD) ischemia model in slices of the postnatal rat somatosensory cortex, we found that immature neurons displayed much more complex behaviors: they initially moderately depolarized during aSD, then transiently repolarised (for up to tens of minutes), and only then passed to terminal depolarization. The ability to fire action potentials was maintained in neurons mildly depolarized during aSD without reaching the level of depolarization block, and these functions were regained in the majority of immature neurons during post-aSD transient repolarization. The amplitude of depolarization and the probability of depolarization block during aSD increased, whereas transient post-SD repolarization levels and duration, and associated recovery in neuronal firing decreased with age. By the end of the first postnatal month, aSD acquired an adult-like phenotype, where depolarization during aSD merged with terminal depolarization and the phase of transient recovery was lost. Thus, changes in neuronal function during aSD undergo remarkable developmental changes that may contribute to lower susceptibility of the immature neurons to ischemia.
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Affiliation(s)
- Azat Gainutdinov
- Laboratory of Neurobiology, Institute of Fundamental Medicine and Biology, Kazan Federal University, Kazan, Russia
- INMED—INSERM, Aix-Marseille University, Marseille, France
| | - Elvira Juzekaeva
- Laboratory of Neurobiology, Institute of Fundamental Medicine and Biology, Kazan Federal University, Kazan, Russia
| | - Marat Mukhtarov
- Laboratory of Neurobiology, Institute of Fundamental Medicine and Biology, Kazan Federal University, Kazan, Russia
| | - Roustem Khazipov
- Laboratory of Neurobiology, Institute of Fundamental Medicine and Biology, Kazan Federal University, Kazan, Russia
- INMED—INSERM, Aix-Marseille University, Marseille, France
- *Correspondence: Roustem Khazipov
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Tureckova J, Kamenicka M, Kolenicova D, Filipi T, Hermanova Z, Kriska J, Meszarosova L, Pukajova B, Valihrach L, Androvic P, Zucha D, Chmelova M, Vargova L, Anderova M. Compromised Astrocyte Swelling/Volume Regulation in the Hippocampus of the Triple Transgenic Mouse Model of Alzheimer’s Disease. Front Aging Neurosci 2022; 13:783120. [PMID: 35153718 PMCID: PMC8829436 DOI: 10.3389/fnagi.2021.783120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2021] [Accepted: 12/27/2021] [Indexed: 11/13/2022] Open
Abstract
In this study, we aimed to disclose the impact of amyloid-β toxicity and tau pathology on astrocyte swelling, their volume recovery and extracellular space (ECS) diffusion parameters, namely volume fraction (α) and tortuosity (λ), in a triple transgenic mouse model of Alzheimer’s disease (3xTg-AD). Astrocyte volume changes, which reflect astrocyte ability to take up ions/neurotransmitters, were quantified during and after exposure to hypo-osmotic stress, or hyperkalemia in acute hippocampal slices, and were correlated with alterations in ECS diffusion parameters. Astrocyte volume and ECS diffusion parameters were monitored during physiological aging (controls) and during AD progression in 3-, 9-, 12- and 18-month-old mice. In the hippocampus of controls α gradually declined with age, while it remained unaffected in 3xTg-AD mice during the entire time course. Moreover, age-related increases in λ occurred much earlier in 3xTg-AD animals than in controls. In 3xTg-AD mice changes in α induced by hypo-osmotic stress or hyperkalemia were comparable to those observed in controls, however, AD progression affected α recovery following exposure to both. Compared to controls, a smaller astrocyte swelling was detected in 3xTg-AD mice only during hyperkalemia. Since we observed a large variance in astrocyte swelling/volume regulation, we divided them into high- (HRA) and low-responding astrocytes (LRA). In response to hyperkalemia, the incidence of LRA was higher in 3xTg-AD mice than in controls, which may also reflect compromised K+ and neurotransmitter uptake. Furthermore, we performed single-cell RT-qPCR to identify possible age-related alterations in astrocytic gene expression profiles. Already in 3-month-old 3xTg-AD mice, we detected a downregulation of genes affecting the ion/neurotransmitter uptake and cell volume regulation, namely genes of glutamate transporters, α2β2 subunit of Na+/K+-ATPase, connexin 30 or Kir4.1 channel. In conclusion, the aged hippocampus of 3xTg-AD mice displays an enlarged ECS volume fraction and an increased number of obstacles, which emerge earlier than in physiological aging. Both these changes may strongly affect intercellular communication and influence astrocyte ionic/neurotransmitter uptake, which becomes impaired during aging and this phenomenon is manifested earlier in 3xTg-AD mice. The increased incidence of astrocytes with limited ability to take up ions/neurotransmitters may further add to a cytotoxic environment.
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Affiliation(s)
- Jana Tureckova
- Department of Cellular Neurophysiology, Institute of Experimental Medicine, Czech Academy of Sciences, Prague, Czechia
- *Correspondence: Jana Tureckova,
| | - Monika Kamenicka
- Department of Cellular Neurophysiology, Institute of Experimental Medicine, Czech Academy of Sciences, Prague, Czechia
- Second Faculty of Medicine, Charles University, Prague, Czechia
| | - Denisa Kolenicova
- Department of Cellular Neurophysiology, Institute of Experimental Medicine, Czech Academy of Sciences, Prague, Czechia
- Second Faculty of Medicine, Charles University, Prague, Czechia
| | - Tereza Filipi
- Department of Cellular Neurophysiology, Institute of Experimental Medicine, Czech Academy of Sciences, Prague, Czechia
- Second Faculty of Medicine, Charles University, Prague, Czechia
| | - Zuzana Hermanova
- Department of Cellular Neurophysiology, Institute of Experimental Medicine, Czech Academy of Sciences, Prague, Czechia
- Second Faculty of Medicine, Charles University, Prague, Czechia
| | - Jan Kriska
- Department of Cellular Neurophysiology, Institute of Experimental Medicine, Czech Academy of Sciences, Prague, Czechia
| | - Lenka Meszarosova
- Department of Cellular Neurophysiology, Institute of Experimental Medicine, Czech Academy of Sciences, Prague, Czechia
| | - Barbora Pukajova
- Department of Cellular Neurophysiology, Institute of Experimental Medicine, Czech Academy of Sciences, Prague, Czechia
| | - Lukas Valihrach
- Laboratory of Gene Expression, Institute of Biotechnology, Czech Academy of Sciences, Vestec, Czechia
| | - Peter Androvic
- Laboratory of Gene Expression, Institute of Biotechnology, Czech Academy of Sciences, Vestec, Czechia
| | - Daniel Zucha
- Laboratory of Gene Expression, Institute of Biotechnology, Czech Academy of Sciences, Vestec, Czechia
- Faculty of Chemical Technology, University of Chemistry and Technology, Prague, Czechia
| | - Martina Chmelova
- Department of Cellular Neurophysiology, Institute of Experimental Medicine, Czech Academy of Sciences, Prague, Czechia
- Second Faculty of Medicine, Charles University, Prague, Czechia
| | - Lydia Vargova
- Department of Cellular Neurophysiology, Institute of Experimental Medicine, Czech Academy of Sciences, Prague, Czechia
- Second Faculty of Medicine, Charles University, Prague, Czechia
| | - Miroslava Anderova
- Department of Cellular Neurophysiology, Institute of Experimental Medicine, Czech Academy of Sciences, Prague, Czechia
- Second Faculty of Medicine, Charles University, Prague, Czechia
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Mathew AA, Panonnummal R. Cortical spreading depression: culprits and mechanisms. Exp Brain Res 2022; 240:733-749. [DOI: 10.1007/s00221-022-06307-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2021] [Accepted: 01/06/2022] [Indexed: 02/14/2023]
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9
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Larner A. Transient global amnesia: model, mechanism, hypothesis. Cortex 2022; 149:137-147. [DOI: 10.1016/j.cortex.2022.01.011] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2021] [Revised: 11/13/2021] [Accepted: 01/19/2022] [Indexed: 01/03/2023]
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Atakro CA. Knowledge of Ghanaian Graduating Undergraduate Nurses About Ageing. SAGE Open Nurs 2021; 7:23779608211020957. [PMID: 34423128 PMCID: PMC8371287 DOI: 10.1177/23779608211020957] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2020] [Revised: 04/19/2021] [Accepted: 05/07/2021] [Indexed: 11/17/2022] Open
Abstract
Introduction Knowledge on ageing has an impact on the quality of care provided to older people. Although older Ghanaians provide various forms of support to family and communities, many of them experience poor nursing care in the Ghanaian health system. There is, however, dearth of evidence regarding knowledge of ageing among Ghanaian nurses. Objective This study therefore used a descriptive survey approach to investigate knowledge of graduating undergraduate nurses on physiological, and psychosocial changes in ageing. Methods Seventy graduating undergraduate nurses were surveyed to identify their knowledge on physiological and psychosocial changes leading to care needs of older people in Ghana. Three undergraduate nursing programs with gerontological nursing courses were purposively selected for the study. Descriptive statistics were used to analyze the data in order to present quantitative descriptions of variables in this study. Results The response rate in the study was 42%. Findings of the study show graduating undergraduate nursing students have inadequate knowledge on ageing. Several gaps in knowledge regarding ageing were identified. Although undergraduate nursing schools had gerontological nursing courses in their programs, over 90% of participating graduating nursing students indicated pain, anxiety and depression are normal aspects in the ageing process. Conclusion It is imperative to improve the current curricula content on gerontological nursing in Ghanaian nursing schools to equip nurses with knowledge and skills needed to provide quality healthcare to older people in Ghana. Improving knowledge on ageing through evidence-informed gerontological nursing curricula content will lead to better nursing care of older Ghanaians. Providing educational opportunities for improved quality nursing care of older Ghanaians is in line with the United Nations (UN) Sustainable Development Goal 3, which aims at providing equal and quality healthcare to all age groups by 2030.
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Affiliation(s)
- Confidence Alorse Atakro
- School of Nursing and Midwifery, Faculty of Health and Applied Sciences, Christian Service University College, Kumasi, Ghana
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11
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Kalia M, Meijer HGE, van Gils SA, van Putten MJAM, Rose CR. Ion dynamics at the energy-deprived tripartite synapse. PLoS Comput Biol 2021; 17:e1009019. [PMID: 34143772 PMCID: PMC8244923 DOI: 10.1371/journal.pcbi.1009019] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2020] [Revised: 06/30/2021] [Accepted: 04/28/2021] [Indexed: 01/09/2023] Open
Abstract
The anatomical and functional organization of neurons and astrocytes at 'tripartite synapses' is essential for reliable neurotransmission, which critically depends on ATP. In low energy conditions, synaptic transmission fails, accompanied by a breakdown of ion gradients, changes in membrane potentials and cell swelling. The resulting cellular damage and cell death are causal to the often devastating consequences of an ischemic stroke. The severity of ischemic damage depends on the age and the brain region in which a stroke occurs, but the reasons for this differential vulnerability are far from understood. In the present study, we address this question by developing a comprehensive biophysical model of a glutamatergic synapse to identify key determinants of synaptic failure during energy deprivation. Our model is based on fundamental biophysical principles, includes dynamics of the most relevant ions, i.e., Na+, K+, Ca2+, Cl- and glutamate, and is calibrated with experimental data. It confirms the critical role of the Na+/K+-ATPase in maintaining ion gradients, membrane potentials and cell volumes. Our simulations demonstrate that the system exhibits two stable states, one physiological and one pathological. During energy deprivation, the physiological state may disappear, forcing a transit to the pathological state, which can be reverted when blocking voltage-gated Na+ and K+ channels. Our model predicts that the transition to the pathological state is favoured if the extracellular space fraction is small. A reduction in the extracellular space volume fraction, as, e.g. observed with ageing, will thus promote the brain's susceptibility to ischemic damage. Our work provides new insights into the brain's ability to recover from energy deprivation, with translational relevance for diagnosis and treatment of ischemic strokes.
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Affiliation(s)
- Manu Kalia
- Applied Analysis, Department of Applied Mathematics, University of Twente, Enschede, The Netherlands
- * E-mail:
| | - Hil G. E. Meijer
- Applied Analysis, Department of Applied Mathematics, University of Twente, Enschede, The Netherlands
| | - Stephan A. van Gils
- Applied Analysis, Department of Applied Mathematics, University of Twente, Enschede, The Netherlands
| | | | - Christine R. Rose
- Institute of Neurobiology, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
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Frank R, Bari F, Menyhárt Á, Farkas E. Comparative analysis of spreading depolarizations in brain slices exposed to osmotic or metabolic stress. BMC Neurosci 2021; 22:33. [PMID: 33941084 PMCID: PMC8094470 DOI: 10.1186/s12868-021-00637-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2021] [Accepted: 04/20/2021] [Indexed: 12/21/2022] Open
Abstract
BACKGROUND Recurrent spreading depolarizations (SDs) occur in stroke and traumatic brain injury and are considered as a hallmark of injury progression. The complexity of conditions associated with SD in the living brain encouraged researchers to study SD in live brain slice preparations, yet methodological differences among laboratories complicate integrative data interpretation. Here we provide a comparative evaluation of SD evolution in live brain slices, in response to selected SD triggers and in various media, under otherwise standardized experimental conditions. METHODS Rat live coronal brain slices (350 μm) were prepared (n = 51). Hypo-osmotic medium (Na+ content reduced from 130 to 60 mM, HM) or oxygen-glucose deprivation (OGD) were applied to cause osmotic or ischemic challenge. Brain slices superfused with artificial cerebrospinal fluid (aCSF) served as control. SDs were evoked in the control condition with pressure injection of KCl or electric stimulation. Local field potential (LFP) was recorded via an intracortical glass capillary electrode, or intrinsic optical signal imaging was conducted at white light illumination to characterize SDs. TTC and hematoxylin-eosin staining were used to assess tissue damage. RESULTS Severe osmotic stress or OGD provoked a spontaneous SD. In contrast with SDs triggered in aCSF, these spontaneous depolarizations were characterized by incomplete repolarization and prolonged duration. Further, cortical SDs under HM or OGD propagated over the entire cortex and occassionally invaded the striatum, while SDs in aCSF covered a significantly smaller cortical area before coming to a halt, and never spread to the striatum. SDs in HM displayed the greatest amplitude and the most rapid propagation velocity. Finally, spontaneous SD in HM and especially under OGD was followed by tissue injury. CONCLUSIONS While the failure of Na+/K+ ATP-ase is thought to impair tissue recovery from OGD-related SD, the tissue swelling-related hyper excitability and the exhaustion of astrocyte buffering capacity are suggested to promote SD evolution under osmotic stress. In contrast with OGD, SD propagating under hypo-osmotic condition is not terminal, yet it is associated with irreversible tissue injury. Further investigation is required to understand the mechanistic similarities or differences between the evolution of SDs spontaneously occurring in HM and under OGD.
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Affiliation(s)
- Rita Frank
- Department of Medical Physics and Informatics, Faculty of Medicine and Faculty of Science and Informatics, University of Szeged, Korányi fasor 9, 6720, Szeged, Hungary
| | - Ferenc Bari
- Department of Medical Physics and Informatics, Faculty of Medicine and Faculty of Science and Informatics, University of Szeged, Korányi fasor 9, 6720, Szeged, Hungary
| | - Ákos Menyhárt
- Department of Medical Physics and Informatics, Faculty of Medicine and Faculty of Science and Informatics, University of Szeged, Korányi fasor 9, 6720, Szeged, Hungary.
| | - Eszter Farkas
- Department of Medical Physics and Informatics, Faculty of Medicine and Faculty of Science and Informatics, University of Szeged, Korányi fasor 9, 6720, Szeged, Hungary.
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13
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Chiu KM, Lin TY, Lee MY, Lu CW, Wang MJ, Wang SJ. Typhaneoside Suppresses Glutamate Release Through Inhibition of Voltage-Dependent Calcium Entry in Rat Cerebrocortical Nerve Terminals. Chem Res Toxicol 2021; 34:1286-1295. [PMID: 33621091 DOI: 10.1021/acs.chemrestox.0c00446] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Glutamate is the major excitatory neurotransmitter in the brain and is involved in many brain functions. In this study, we investigated whether typhaneoside, a flavonoid from Typhae angustifolia pollen, affects endogenous glutamate release from rat cortical synaptosomes. Using a one-line enzyme-coupled fluorometric assay, glutamate release stimulated by the K+ channel blocker 4-aminopyridine was monitored to explore the possible underlying mechanisms. The vesicular transporter inhibitor bafilomycin A1 and chelation of extracellular Ca2+ ions with EGTA suppressed the effect of typhaneoside on the induced glutamate release. Nevertheless, the typhaneoside activity has not been affected by the glutamate transporter inhibitor dl-threo-beta-benzyloxyaspartate. The synaptosomal plasma membrane potential was assayed using a membrane potential-sensitive dye DiSC3(5), and cytosolic Ca2+ concentrations ([Ca2+]C) was monitored by a Ca2+ indicator Fura-2. Results showed that typhaneoside did not alter the synaptosomal membrane potential but lowered 4-aminopyridine-induced increases in [Ca2+]C. Furthermore, the Cav2.2 (N-type) channel blocker ω-conotoxin GVIA blocked Ca2+ entry and inhibited the effect of typhaneoside on 4-aminopyridine-induced glutamate release. However, the inhibitor of intracellular Ca2+ release dantrolene and the mitochondrial Na+/Ca2+ exchanger blocker 7-chloro-5-(2-chloropheny)-1,5-dihydro-4,1-benzothiazepin-2(3H)-one have no effect on the suppression of glutamate release mediated by typhaneoside. Moreover, inhibition of mitogen-activated protein kinase (MAPK)/extracellular signal-regulated kinase (ERK) prevented the inhibitory effect of typhaneoside on induced glutamate release. Typhaneoside reduced 4-aminopyridine-induced phosphorylation of ERK1/2 and the major presynaptic ERK target synapsin I, which is a synaptic vesicle-associated protein. In conclusion, these findings suggest a role for typhaneoside in modulating glutamate release by suppressing voltage-dependent Ca2+ channel mediated presynaptic Ca2+ influx and the MAPK/ERK/synapsin I signaling cascade.
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Affiliation(s)
- Kuan-Ming Chiu
- Division of Cardiovascular Surgery, Cardiovascular Center, Far-Eastern Memorial Hospital, New Taipei City 22060, Taiwan.,Department of Nursing, Oriental Institute of Technology, New Taipei City 22060, Taiwan.,Department of Photonics Engineering, Yuan Ze University, Taoyuan City 32003, Taiwan
| | - Tzu-Yu Lin
- Department of Anesthesiology, Far-Eastern Memorial Hospital, New Taipei City 22060, Taiwan.,Department of Mechanical Engineering, Yuan Ze University, Taoyuan City 32003, Taiwan
| | - Ming-Yi Lee
- Division of Cardiovascular Surgery, Cardiovascular Center, Far-Eastern Memorial Hospital, New Taipei City 22060, Taiwan
| | - Cheng-Wei Lu
- Department of Anesthesiology, Far-Eastern Memorial Hospital, New Taipei City 22060, Taiwan.,Department of Mechanical Engineering, Yuan Ze University, Taoyuan City 32003, Taiwan
| | - Ming-Jiuh Wang
- Department of Anesthesiology, National Taiwan University Hospital, Taipei City 100225, Taiwan
| | - Su-Jane Wang
- Research Center for Chinese Herbal Medicine, College of Human Ecology, Chang Gung University of Science and Technology, Taoyuan City 33303, Taiwan.,School of Medicine, Fu Jen Catholic University, New Taipei City 24205, Taiwan
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14
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Candelario-Jalil E, Paul S. Impact of aging and comorbidities on ischemic stroke outcomes in preclinical animal models: A translational perspective. Exp Neurol 2021; 335:113494. [PMID: 33035516 PMCID: PMC7874968 DOI: 10.1016/j.expneurol.2020.113494] [Citation(s) in RCA: 32] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2020] [Revised: 09/25/2020] [Accepted: 10/02/2020] [Indexed: 12/16/2022]
Abstract
Ischemic stroke is a highly complex and devastating neurological disease. The sudden loss of blood flow to a brain region due to an ischemic insult leads to severe damage to that area resulting in the formation of an infarcted tissue, also known as the ischemic core. This is surrounded by the peri-infarct region or penumbra that denotes the functionally impaired but potentially salvageable tissue. Thus, the penumbral tissue is the main target for the development of neuroprotective strategies to minimize the extent of ischemic brain damage by timely therapeutic intervention. Given the limitations of reperfusion therapies with recombinant tissue plasminogen activator or mechanical thrombectomy, there is high enthusiasm to combine reperfusion therapy with neuroprotective strategies to further reduce the progression of ischemic brain injury. Till date, a large number of candidate neuroprotective drugs have been identified as potential therapies based on highly promising results from studies in rodent ischemic stroke models. However, none of these interventions have shown therapeutic benefits in stroke patients in clinical trials. In this review article, we discussed the urgent need to utilize preclinical models of ischemic stroke that more accurately mimic the clinical conditions in stroke patients by incorporating aged animals and animal stroke models with comorbidities. We also outlined the recent findings that highlight the significant differences in stroke outcome between young and aged animals, and how major comorbid conditions such as hypertension, diabetes, obesity and hyperlipidemia dramatically increase the vulnerability of the brain to ischemic damage that eventually results in worse functional outcomes. It is evident from these earlier studies that including animal models of aging and comorbidities during the early stages of drug development could facilitate the identification of neuroprotective strategies with high likelihood of success in stroke clinical trials.
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Affiliation(s)
- Eduardo Candelario-Jalil
- Department of Neuroscience, McKnight Brain Institute, University of Florida, Gainesville, FL 32610, USA.
| | - Surojit Paul
- Department of Neurology, University of New Mexico Health Sciences Center, Albuquerque, NM 87131, USA
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15
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Varga DP, Menyhárt Á, Pósfai B, Császár E, Lénárt N, Cserép C, Orsolits B, Martinecz B, Szlepák T, Bari F, Farkas E, Dénes Á. Microglia alter the threshold of spreading depolarization and related potassium uptake in the mouse brain. J Cereb Blood Flow Metab 2020; 40:S67-S80. [PMID: 31987008 PMCID: PMC7687034 DOI: 10.1177/0271678x19900097] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Selective elimination of microglia from the brain was shown to dysregulate neuronal Ca2+ signaling and to reduce the incidence of spreading depolarization (SD) during cerebral ischemia. However, the mechanisms through which microglia interfere with SD remained unexplored. Here, we identify microglia as essential modulators of the induction and evolution of SD in the physiologically intact brain in vivo. Confocal- and super-resolution microscopy revealed that a series of SDs induced rapid morphological changes in microglia, facilitated microglial process recruitment to neurons and increased the density of P2Y12 receptors (P2Y12R) on recruited microglial processes. In line with this, depolarization and hyperpolarization during SD were microglia- and P2Y12R-dependent. An absence of microglia was associated with altered potassium uptake after SD and increased the number of c-fos-positive neurons, independently of P2Y12R. Thus, the presence of microglia is likely to be essential to maintain the electrical elicitation threshold and to support the full evolution of SD, conceivably by interfering with the extracellular potassium homeostasis of the brain through sustaining [K+]e re-uptake mechanisms.
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Affiliation(s)
- Dániel P Varga
- Department of Medical Physics and Informatics, University of Szeged, Szeged, Hungary
| | - Ákos Menyhárt
- Department of Medical Physics and Informatics, University of Szeged, Szeged, Hungary
| | - Balázs Pósfai
- Laboratory of Neuroimmunology, Institute of Experimental Medicine, Budapest, Hungary.,Szentágothai János Doctoral School of Neuroscience, Semmelweis University, Budapest, Hungary
| | - Eszter Császár
- Laboratory of Neuroimmunology, Institute of Experimental Medicine, Budapest, Hungary.,Szentágothai János Doctoral School of Neuroscience, Semmelweis University, Budapest, Hungary
| | - Nikolett Lénárt
- Laboratory of Neuroimmunology, Institute of Experimental Medicine, Budapest, Hungary
| | - Csaba Cserép
- Laboratory of Neuroimmunology, Institute of Experimental Medicine, Budapest, Hungary
| | - Barbara Orsolits
- Laboratory of Neuroimmunology, Institute of Experimental Medicine, Budapest, Hungary
| | - Bernadett Martinecz
- Laboratory of Neuroimmunology, Institute of Experimental Medicine, Budapest, Hungary
| | - Tamás Szlepák
- Laboratory of Neuroimmunology, Institute of Experimental Medicine, Budapest, Hungary.,Szentágothai János Doctoral School of Neuroscience, Semmelweis University, Budapest, Hungary
| | - Ferenc Bari
- Department of Medical Physics and Informatics, University of Szeged, Szeged, Hungary
| | - Eszter Farkas
- Department of Medical Physics and Informatics, University of Szeged, Szeged, Hungary
| | - Ádám Dénes
- Laboratory of Neuroimmunology, Institute of Experimental Medicine, Budapest, Hungary
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16
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Major S, Huo S, Lemale CL, Siebert E, Milakara D, Woitzik J, Gertz K, Dreier JP. Direct electrophysiological evidence that spreading depolarization-induced spreading depression is the pathophysiological correlate of the migraine aura and a review of the spreading depolarization continuum of acute neuronal mass injury. GeroScience 2020; 42:57-80. [PMID: 31820363 PMCID: PMC7031471 DOI: 10.1007/s11357-019-00142-7] [Citation(s) in RCA: 42] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2019] [Accepted: 11/20/2019] [Indexed: 02/07/2023] Open
Abstract
Spreading depolarization is observed as a large negative shift of the direct current potential, swelling of neuronal somas, and dendritic beading in the brain's gray matter and represents a state of a potentially reversible mass injury. Its hallmark is the abrupt, massive ion translocation between intraneuronal and extracellular compartment that causes water uptake (= cytotoxic edema) and massive glutamate release. Dependent on the tissue's energy status, spreading depolarization can co-occur with different depression or silencing patterns of spontaneous activity. In adequately supplied tissue, spreading depolarization induces spreading depression of activity. In severely ischemic tissue, nonspreading depression of activity precedes spreading depolarization. The depression pattern determines the neurological deficit which is either spreading such as in migraine aura or migraine stroke or nonspreading such as in transient ischemic attack or typical stroke. Although a clinical distinction between spreading and nonspreading focal neurological deficits is useful because they are associated with different probabilities of permanent damage, it is important to note that spreading depolarization, the neuronal injury potential, occurs in all of these conditions. Here, we first review the scientific basis of the continuum of spreading depolarizations. Second, we highlight the transition zone of the continuum from reversibility to irreversibility using clinical cases of aneurysmal subarachnoid hemorrhage and cerebral amyloid angiopathy. These illustrate how modern neuroimaging and neuromonitoring technologies increasingly bridge the gap between basic sciences and clinic. For example, we provide direct electrophysiological evidence for the first time that spreading depolarization-induced spreading depression is the pathophysiological correlate of the migraine aura.
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Affiliation(s)
- Sebastian Major
- Center for Stroke Research, Campus Charité Mitte, Charité University Medicine Berlin, Charitéplatz 1, 10117, Berlin, Germany
- Department of Experimental Neurology, Charité-Universitätsmedizin Berlin, Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany
- Department of Neurology, Charité-Universitätsmedizin Berlin, Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany
| | - Shufan Huo
- Center for Stroke Research, Campus Charité Mitte, Charité University Medicine Berlin, Charitéplatz 1, 10117, Berlin, Germany
- Department of Neurology, Charité-Universitätsmedizin Berlin, Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany
| | - Coline L Lemale
- Center for Stroke Research, Campus Charité Mitte, Charité University Medicine Berlin, Charitéplatz 1, 10117, Berlin, Germany
- Department of Experimental Neurology, Charité-Universitätsmedizin Berlin, Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany
| | - Eberhard Siebert
- Department of Neuroradiology, Charité-Universitätsmedizin Berlin, Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany
| | - Denny Milakara
- Solution Centre for Image Guided Local Therapies (STIMULATE), Otto-von-Guericke-University, Magdeburg, Germany
| | - Johannes Woitzik
- Evangelisches Krankenhaus Oldenburg, University of Oldenburg, Oldenburg, Germany
| | - Karen Gertz
- Center for Stroke Research, Campus Charité Mitte, Charité University Medicine Berlin, Charitéplatz 1, 10117, Berlin, Germany
- Department of Experimental Neurology, Charité-Universitätsmedizin Berlin, Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany
- Department of Neurology, Charité-Universitätsmedizin Berlin, Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany
| | - Jens P Dreier
- Center for Stroke Research, Campus Charité Mitte, Charité University Medicine Berlin, Charitéplatz 1, 10117, Berlin, Germany.
- Department of Experimental Neurology, Charité-Universitätsmedizin Berlin, Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany.
- Department of Neurology, Charité-Universitätsmedizin Berlin, Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany.
- Bernstein Center for Computational Neuroscience Berlin, Berlin, Germany.
- Einstein Center for Neurosciences Berlin, Berlin, Germany.
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17
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Varga DP, Szabó Í, Varga VÉ, Menhyárt Á, M Tóth O, Kozma M, Bálint AR, Krizbai IA, Bari F, Farkas E. The antagonism of prostaglandin FP receptors inhibits the evolution of spreading depolarization in an experimental model of global forebrain ischemia. Neurobiol Dis 2020; 137:104780. [PMID: 31991249 DOI: 10.1016/j.nbd.2020.104780] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2019] [Revised: 01/21/2020] [Accepted: 01/24/2020] [Indexed: 12/13/2022] Open
Abstract
Spontaneous, recurrent spreading depolarizations (SD) are increasingly more appreciated as a pathomechanism behind ischemic brain injuries. Although the prostaglandin F2α - FP receptor signaling pathway has been proposed to contribute to neurodegeneration, it has remained unexplored whether FP receptors are implicated in SD or the coupled cerebral blood flow (CBF) response. We set out here to test the hypothesis that FP receptor blockade may achieve neuroprotection by the inhibition of SD. Global forebrain ischemia/reperfusion was induced in anesthetized rats by the bilateral occlusion and later release of the common carotid arteries. An FP receptor antagonist (AL-8810; 1 mg/bwkg) or its vehicle were administered via the femoral vein 10 min later. Two open craniotomies on the right parietal bone served the elicitation of SD with 1 M KCl, and the acquisition of local field potential. CBF was monitored with laser speckle contrast imaging over the thinned parietal bone. Apoptosis and microglia activation, as well as FP receptor localization were evaluated with immunohistochemistry. The data demonstrate that the antagonism of FP receptors suppressed SD in the ischemic rat cerebral cortex and reduced the duration of recurrent SDs by facilitating repolarization. In parallel, FP receptor antagonism improved perfusion in the ischemic cerebral cortex, and attenuated hypoemic CBF responses associated with SD. Further, FP receptor antagonism appeared to restrain apoptotic cell death related to SD recurrence. In summary, the antagonism of FP receptors (located at the neuro-vascular unit, neurons, astrocytes and microglia) emerges as a promising approach to inhibit the evolution of SDs in cerebral ischemia.
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Affiliation(s)
- Dániel P Varga
- Department of Medical Physics and Informatics, Faculty of Medicine, University of Szeged; H-6720 Szeged, Korányi fasor 9, Hungary
| | - Írisz Szabó
- Department of Medical Physics and Informatics, Faculty of Medicine, University of Szeged; H-6720 Szeged, Korányi fasor 9, Hungary
| | - Viktória É Varga
- Department of Medical Physics and Informatics, Faculty of Medicine, University of Szeged; H-6720 Szeged, Korányi fasor 9, Hungary
| | - Ákos Menhyárt
- Department of Medical Physics and Informatics, Faculty of Medicine, University of Szeged; H-6720 Szeged, Korányi fasor 9, Hungary
| | - Orsolya M Tóth
- Department of Medical Physics and Informatics, Faculty of Medicine, University of Szeged; H-6720 Szeged, Korányi fasor 9, Hungary
| | - Mihály Kozma
- Physiology and Pathology of the Blood-Brain Barrier Research Group, Molecular Neurobiology Research Unit, Institute of Biophysics, Biological Research Centre, H-6726 Szeged, Temesvári krt. 62, Hungary
| | - Armand R Bálint
- Department of Medical Physics and Informatics, Faculty of Medicine, University of Szeged; H-6720 Szeged, Korányi fasor 9, Hungary
| | - István A Krizbai
- Physiology and Pathology of the Blood-Brain Barrier Research Group, Molecular Neurobiology Research Unit, Institute of Biophysics, Biological Research Centre, H-6726 Szeged, Temesvári krt. 62, Hungary; Institute of Life Sciences, Vasile Goldis Western University; Revolutiei Blvd n°94, Arad 310025, Romania
| | - Ferenc Bari
- Department of Medical Physics and Informatics, Faculty of Medicine, University of Szeged; H-6720 Szeged, Korányi fasor 9, Hungary
| | - Eszter Farkas
- Department of Medical Physics and Informatics, Faculty of Medicine, University of Szeged; H-6720 Szeged, Korányi fasor 9, Hungary.
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18
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Tóth OM, Menyhárt Á, Varga VÉ, Hantosi D, Ivánkovits-Kiss O, Varga DP, Szabó Í, Janovák L, Dékány I, Farkas E, Bari F. Chitosan nanoparticles release nimodipine in response to tissue acidosis to attenuate spreading depolarization evoked during forebrain ischemia. Neuropharmacology 2020; 162:107850. [DOI: 10.1016/j.neuropharm.2019.107850] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2019] [Revised: 11/05/2019] [Accepted: 11/08/2019] [Indexed: 02/07/2023]
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19
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Bálint AR, Puskás T, Menyhárt Á, Kozák G, Szenti I, Kónya Z, Marek T, Bari F, Farkas E. Aging Impairs Cerebrovascular Reactivity at Preserved Resting Cerebral Arteriolar Tone and Vascular Density in the Laboratory Rat. Front Aging Neurosci 2019; 11:301. [PMID: 31780917 PMCID: PMC6856663 DOI: 10.3389/fnagi.2019.00301] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2019] [Accepted: 10/21/2019] [Indexed: 12/26/2022] Open
Abstract
The age-related (mal)adaptive modifications of the cerebral microvascular system have been implicated in cognitive impairment and worse outcomes after ischemic stroke. The magnitude of the hyperemic response to spreading depolarization (SD), a recognized principle of ischemic lesion development has also been found to be reduced by aging. Here, we set out to investigate whether the SD-coupled reactivity of the pial arterioles is subject to aging, and whether concomitant vascular rarefaction may contribute to the age-related insufficiency of the cerebral blood flow (CBF) response. CBF was assessed with laser-speckle contrast analysis (LASCA), and the tone adjustment of pial arterioles was followed with intrinsic optical signal (IOS) imaging at green light illumination through a closed cranial window created over the parietal cortex of isoflurane-anesthetized young (2 months old) and old (18 months old) male Sprague-Dawley rats. Global forebrain ischemia and later reperfusion were induced by the bilateral occlusion and later release of both common carotid arteries. SDs were elicited repeatedly with topical 1M KCl. Pial vascular density was measured in green IOS images of the brain surface, while the density and resting diameter of the cortical penetrating vasculature was estimated with micro-computed tomography of paraformaldehyde-fixed cortical samples. Whilst pial arteriolar dilation in response to SD or ischemia induction were found reduced in the old rat brain, the density and resting diameter of pial cortical vessels, and the degree of SD-related oligemia emerged as variables unaffected by age in our experiments. Spatial flow distribution analysis identified an age-related shift to a greater representation of higher flow ranges in the reperfused cortex. According to our data, impairment of functional arteriolar dilation, at preserved vascular density and resting vascular tone, may be implicated in the age-related deficit of the CBF response to SD, and possibly in the reduced efficacy of neurovascular coupling in the aging brain. SD has been recognized as a potent pathophysiological contributor to ischemic lesion expansion, in part because of the insufficiency of the associated CBF response. Therefore, the age-related impairment of cerebral vasoreactivity as shown here is suggested to contribute to the age-related acceleration of ischemic lesion development.
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Affiliation(s)
- Armand R. Bálint
- Department of Medical Physics and Informatics, Faculty of Medicine, University of Szeged, Szeged, Hungary
| | - Tamás Puskás
- Department of Medical Physics and Informatics, Faculty of Medicine, University of Szeged, Szeged, Hungary
| | - Ákos Menyhárt
- Department of Medical Physics and Informatics, Faculty of Medicine, University of Szeged, Szeged, Hungary
| | - Gábor Kozák
- Department of Physiology, Faculty of Medicine, University of Szeged, Szeged, Hungary
| | - Imre Szenti
- Department of Applied and Environmental Chemistry, Interdisciplinary Excellence Centre, University of Szeged, Szeged, Hungary
| | - Zoltán Kónya
- Department of Applied and Environmental Chemistry, Interdisciplinary Excellence Centre, University of Szeged, Szeged, Hungary
- MTA-SZTE Reaction Kinetics and Surface Chemistry Research Group, University of Szeged, Szeged, Hungary
| | - Tamás Marek
- Department of Medical Physics and Informatics, Faculty of Medicine, University of Szeged, Szeged, Hungary
| | - Ferenc Bari
- Department of Medical Physics and Informatics, Faculty of Medicine, University of Szeged, Szeged, Hungary
| | - Eszter Farkas
- Department of Medical Physics and Informatics, Faculty of Medicine, University of Szeged, Szeged, Hungary
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20
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Francisco EDS, Mendes-da-Silva RF, de Castro CBL, Soares GDSF, Guedes RCA. Taurine/Pilocarpine Interaction in the Malnourished Rat Brain: A Behavioral, Electrophysiological, and Immunohistochemical Analysis. Front Neurosci 2019; 13:981. [PMID: 31619952 PMCID: PMC6759493 DOI: 10.3389/fnins.2019.00981] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2019] [Accepted: 08/30/2019] [Indexed: 12/05/2022] Open
Abstract
This study aimed to evaluate the possible protective role of taurine on anxiety-like behavior, brain electrical activity and glial cell immunoreactivity in well-nourished and malnourished rats that were treated with a subconvulsing dose of pilocarpine. Newborn Wistar rats were subjected to normal or unfavorable lactation conditions, represented by the suckling of litters with 9 or 15 pups, resulting in well-nourished and malnourished animals, respectively. Each nutritional group was split into five subgroups that were treated from postnatal day (PND) 35 to 55 with 300 mg/kg/day of taurine + 45 mg/kg/day of pilocarpine (group T + P), taurine only (group T), pilocarpine only (group P), vehicle control (group V), or not treated control (group naïve; Nv). At PND56-58, the groups were subjected to the elevated plus-maze behavioral tests. Glycemia was measured on PND59. Between PND60 and PND65, the cortical spreading depression (CSD) was recorded in the cerebral cortex, and the levels of malondialdehyde and microglial and astrocyte immunoreactivity were evaluated in the cortex and hippocampus. Our data indicate that treatment with taurine and pilocarpine resulted in anxiolytic-like and anxiogenic behavior, respectively, and that nutritional deficiency modulated these effects. Both treatments decelerated CSD propagation and modulated GFAP- and Iba1-containing glial cells. Pilocarpine reduced body weight and glycemia, and administration of taurine was not able to attenuate the effects of pilocarpine. The molecular mechanisms underlying taurine action on behavioral and electrophysiological parameters in the normal and altered brain remain to be further explored.
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21
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Guedes RCA, Abadie-Guedes R. Brain Aging and Electrophysiological Signaling: Revisiting the Spreading Depression Model. Front Aging Neurosci 2019; 11:136. [PMID: 31231207 PMCID: PMC6567796 DOI: 10.3389/fnagi.2019.00136] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2018] [Accepted: 05/21/2019] [Indexed: 12/31/2022] Open
Abstract
As a consequence of worldwide improvement in health care, the aging portion of the human population has increased, now representing a higher proportion of the total population. This fact raises great concern regarding how to age while maintaining good brain function. Very often, alterations in brain electrophysiological signaling are associated with age-dependent functional disorders of the brain. Therefore, animal models suitable for the study of age-related changes in electrical activity of the brain can be very useful. Herein, we review changes in brain electrophysiological features as a function of age by analyzing studies in the rat brain on the phenomenon known as cortical spreading depression (CSD). Alterations in the brain’s capability to generate and propagate CSD may be related to differences in the propensity to develop certain neurological diseases, such as epilepsy, stroke, and migraine, which can biunivocally interact with the aging process. In this review, we revisit ours and others’ previous studies on electrophysiological features of the CSD phenomenon, such as its velocity of propagation and amplitude and duration of its slow negative DC shift, as a function of the animal age, as well as the interaction between age and other factors, such as ethanol consumption, physical exercise, and nutritional status. In addition, we discuss one relatively new feature through which CSD modulates brain signaling: the ability to potentiate the brain’s spontaneous electrical activity. We conclude that the CSD model might importantly contribute to a better understanding of the aging/brain signaling relationship.
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Affiliation(s)
| | - Ricardo Abadie-Guedes
- Departamento de Fisiologia e Farmacologia, Universidade Federal de Pernambuco, Recife, Brazil
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22
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Harriott AM, Takizawa T, Chung DY, Chen SP. Spreading depression as a preclinical model of migraine. J Headache Pain 2019; 20:45. [PMID: 31046659 PMCID: PMC6734429 DOI: 10.1186/s10194-019-1001-4] [Citation(s) in RCA: 58] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2018] [Accepted: 04/18/2019] [Indexed: 01/12/2023] Open
Abstract
Spreading depression (SD) is a slowly propagating wave of near-complete depolarization of neurons and glial cells across the cortex. SD is thought to contribute to the underlying pathophysiology of migraine aura, and possibly also an intrinsic brain activity causing migraine headache. Experimental models of SD have recapitulated multiple migraine-related phenomena and are considered highly translational. In this review, we summarize conventional and novel methods to trigger SD, with specific focus on optogenetic methods. We outline physiological triggers that might affect SD susceptibility, review a multitude of physiological, biochemical, and behavioral consequences of SD, and elaborate their relevance to migraine pathophysiology. The possibility of constructing a recurrent episodic or chronic migraine model using SD is also discussed.
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Affiliation(s)
- Andrea M Harriott
- Neurovascular Research Lab, Department of Radiology, Massachusetts General Hospital, Charlestown, MA, USA.,Department of Neurology, Massachusetts General Hospital, Boston, MA, USA
| | - Tsubasa Takizawa
- Neurovascular Research Lab, Department of Radiology, Massachusetts General Hospital, Charlestown, MA, USA.,Department of Neurology, Keio University School of Medicine, Tokyo, Japan
| | - David Y Chung
- Neurovascular Research Lab, Department of Radiology, Massachusetts General Hospital, Charlestown, MA, USA.,Department of Neurology, Massachusetts General Hospital, Boston, MA, USA
| | - Shih-Pin Chen
- Institute of Clinical Medicine, National Yang-Ming University, Taipei, Taiwan. .,Brain Research Center, National Yang-Ming University, Taipei, Taiwan. .,Division of Translational Research, Department of Medical Research, Taipei Veterans General Hospital, Taipei, Taiwan. .,Department of Neurology, Neurological Institute, Taipei Veterans General Hospital, Taipei, Taiwan.
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