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Li X, Zeng L, Lu X, Chen K, Yu M, Wang B, Zhao M. Early Brain Injury and Neuroprotective Treatment after Aneurysmal Subarachnoid Hemorrhage: A Literature Review. Brain Sci 2023; 13:1083. [PMID: 37509013 PMCID: PMC10376973 DOI: 10.3390/brainsci13071083] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2023] [Revised: 07/11/2023] [Accepted: 07/12/2023] [Indexed: 07/30/2023] Open
Abstract
Early brain injury (EBI) subsequent to subarachnoid hemorrhage (SAH) is strongly associated with delayed cerebral ischemia and poor patient prognosis. Based on investigations into the molecular mechanisms underlying EBI, neurovascular dysfunction resulting from SAH can be attributed to a range of pathological processes, such as microvascular alterations in brain tissue, ionic imbalances, blood-brain barrier disruption, immune-inflammatory responses, oxidative stress, and activation of cell death pathways. Research progress presents a variety of promising therapeutic approaches for the preservation of neurological function following SAH, including calcium channel antagonists, endothelin-1 receptor blockers, antiplatelet agents, anti-inflammatory agents, and anti-oxidative stress agents. EBI can be mitigated following SAH through neuroprotective measures. To enhance our comprehension of the relevant molecular pathways involved in brain injury, including brain ischemia-hypoxic injury, neuroimmune inflammation activation, and the activation of various cell-signaling pathways, following SAH, it is essential to investigate the evolution of these multifaceted pathophysiological processes. Facilitating neural repair following a brain injury is critical for improving patient survival rates and quality of life.
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Affiliation(s)
- Xiaopeng Li
- Department of Neurosurgery, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Lang Zeng
- Department of Neurosurgery, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Xuanzhen Lu
- Department of Neurology, The Third Hospital of Wuhan, Wuhan 430073, China
| | - Kun Chen
- Department of Neurosurgery, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Maling Yu
- Department of Neurology, The Third Hospital of Wuhan, Wuhan 430073, China
| | - Baofeng Wang
- Department of Neurosurgery, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Min Zhao
- Department of Neurosurgery, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
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Siler DA, Semonche AM, Samatham R, Liu JJ, Martini RP, Alkayed NJ, Hinson HE, Cetas JS. Eicosanoid Ratios are Associated with Hemorrhage Severity and Predict Development of Delayed Cerebral Ischemia Following Subarachnoid Hemorrhage. BRAIN HEMORRHAGES 2022. [DOI: 10.1016/j.hest.2022.05.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022] Open
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Solár P, Zamani A, Lakatosová K, Joukal M. The blood-brain barrier and the neurovascular unit in subarachnoid hemorrhage: molecular events and potential treatments. Fluids Barriers CNS 2022; 19:29. [PMID: 35410231 PMCID: PMC8996682 DOI: 10.1186/s12987-022-00312-4] [Citation(s) in RCA: 41] [Impact Index Per Article: 20.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2021] [Accepted: 01/24/2022] [Indexed: 12/12/2022] Open
Abstract
The response of the blood-brain barrier (BBB) following a stroke, including subarachnoid hemorrhage (SAH), has been studied extensively. The main components of this reaction are endothelial cells, pericytes, and astrocytes that affect microglia, neurons, and vascular smooth muscle cells. SAH induces alterations in individual BBB cells, leading to brain homeostasis disruption. Recent experiments have uncovered many pathophysiological cascades affecting the BBB following SAH. Targeting some of these pathways is important for restoring brain function following SAH. BBB injury occurs immediately after SAH and has long-lasting consequences, but most changes in the pathophysiological cascades occur in the first few days following SAH. These changes determine the development of early brain injury as well as delayed cerebral ischemia. SAH-induced neuroprotection also plays an important role and weakens the negative impact of SAH. Supporting some of these beneficial cascades while attenuating the major pathophysiological pathways might be decisive in inhibiting the negative impact of bleeding in the subarachnoid space. In this review, we attempt a comprehensive overview of the current knowledge on the molecular and cellular changes in the BBB following SAH and their possible modulation by various drugs and substances.
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Affiliation(s)
- Peter Solár
- Department of Anatomy, Cellular and Molecular Neurobiology Research Group, Faculty of Medicine, Masaryk University, 625 00, Brno, Czech Republic
- Department of Neurosurgery, Faculty of Medicine, Masaryk University and St. Anne's University Hospital Brno, Pekařská 53, 656 91, Brno, Czech Republic
| | - Alemeh Zamani
- Department of Anatomy, Cellular and Molecular Neurobiology Research Group, Faculty of Medicine, Masaryk University, 625 00, Brno, Czech Republic
| | - Klaudia Lakatosová
- Department of Anatomy, Cellular and Molecular Neurobiology Research Group, Faculty of Medicine, Masaryk University, 625 00, Brno, Czech Republic
| | - Marek Joukal
- Department of Anatomy, Cellular and Molecular Neurobiology Research Group, Faculty of Medicine, Masaryk University, 625 00, Brno, Czech Republic.
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Zhou J, Guo P, Guo Z, Sun X, Chen Y, Feng H. Fluid metabolic pathways after subarachnoid hemorrhage. J Neurochem 2021; 160:13-33. [PMID: 34160835 DOI: 10.1111/jnc.15458] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2021] [Revised: 05/12/2021] [Accepted: 06/20/2021] [Indexed: 01/05/2023]
Abstract
Aneurysmal subarachnoid hemorrhage (aSAH) is a devastating cerebrovascular disease with high mortality and morbidity. In recent years, a large number of studies have focused on the mechanism of early brain injury (EBI) and delayed cerebral ischemia (DCI), including vasospasm, neurotoxicity of hematoma and neuroinflammatory storm, after aSAH. Despite considerable efforts, no novel drugs have significantly improved the prognosis of patients in phase III clinical trials, indicating the need to further re-examine the multifactorial pathophysiological process that occurs after aSAH. The complex pathogenesis is reflected by the destruction of the dynamic balance of the energy metabolism in the nervous system after aSAH, which prevents the maintenance of normal neural function. This review focuses on the fluid metabolic pathways of the central nervous system (CNS), starting with ruptured aneurysms, and discusses the dysfunction of blood circulation, cerebrospinal fluid (CSF) circulation and the glymphatic system during disease progression. It also proposes a hypothesis on the metabolic disorder mechanism and potential therapeutic targets for aSAH patients.
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Affiliation(s)
- Jiru Zhou
- Department of Neurosurgery, The First Affiliated Hospital of Chongqing Medical University, Chongqing, China.,Department of Neurosurgery and State Key Laboratory of Trauma, Burn and Combined Injury, Southwest Hospital, Third Military Medical University (Army Medical University), Chongqing, China.,Chongqing Key Laboratory of Precision Neuromedicine and Neuroregeneration, Southwest Hospital, Third Military Medical University (Army Medical University), Chongqing, China
| | - Peiwen Guo
- Department of Neurosurgery and State Key Laboratory of Trauma, Burn and Combined Injury, Southwest Hospital, Third Military Medical University (Army Medical University), Chongqing, China.,Chongqing Key Laboratory of Precision Neuromedicine and Neuroregeneration, Southwest Hospital, Third Military Medical University (Army Medical University), Chongqing, China
| | - Zongduo Guo
- Department of Neurosurgery, The First Affiliated Hospital of Chongqing Medical University, Chongqing, China
| | - Xiaochuan Sun
- Department of Neurosurgery, The First Affiliated Hospital of Chongqing Medical University, Chongqing, China
| | - Yujie Chen
- Department of Neurosurgery and State Key Laboratory of Trauma, Burn and Combined Injury, Southwest Hospital, Third Military Medical University (Army Medical University), Chongqing, China.,Chongqing Key Laboratory of Precision Neuromedicine and Neuroregeneration, Southwest Hospital, Third Military Medical University (Army Medical University), Chongqing, China
| | - Hua Feng
- Department of Neurosurgery and State Key Laboratory of Trauma, Burn and Combined Injury, Southwest Hospital, Third Military Medical University (Army Medical University), Chongqing, China.,Chongqing Key Laboratory of Precision Neuromedicine and Neuroregeneration, Southwest Hospital, Third Military Medical University (Army Medical University), Chongqing, China
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Lidington D, Kroetsch JT, Bolz SS. Cerebral artery myogenic reactivity: The next frontier in developing effective interventions for subarachnoid hemorrhage. J Cereb Blood Flow Metab 2018; 38:17-37. [PMID: 29135346 PMCID: PMC5757446 DOI: 10.1177/0271678x17742548] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Aneurysmal subarachnoid hemorrhage (SAH) is a devastating cerebral event that kills or debilitates the majority of those afflicted. The blood that spills into the subarachnoid space stimulates profound cerebral artery vasoconstriction and consequently, cerebral ischemia. Thus, once the initial bleeding in SAH is appropriately managed, the clinical focus shifts to maintaining/improving cerebral perfusion. However, current therapeutic interventions largely fail to improve clinical outcome, because they do not effectively restore normal cerebral artery function. This review discusses emerging evidence that perturbed cerebrovascular "myogenic reactivity," a crucial microvascular process that potently dictates cerebral perfusion, is the critical element underlying cerebral ischemia in SAH. In fact, the myogenic mechanism could be the reason why many therapeutic interventions, including "Triple H" therapy, fail to deliver benefit to patients. Understanding the molecular basis for myogenic reactivity changes in SAH holds the key to develop more effective therapeutic interventions; indeed, promising recent advancements fuel optimism that vascular dysfunction in SAH can be corrected to improve outcome.
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Affiliation(s)
- Darcy Lidington
- 1 Department of Physiology, University of Toronto, Toronto, Canada.,2 Toronto Centre for Microvascular Medicine at TBEP, University of Toronto, Toronto, Canada
| | - Jeffrey T Kroetsch
- 1 Department of Physiology, University of Toronto, Toronto, Canada.,2 Toronto Centre for Microvascular Medicine at TBEP, University of Toronto, Toronto, Canada
| | - Steffen-Sebastian Bolz
- 1 Department of Physiology, University of Toronto, Toronto, Canada.,2 Toronto Centre for Microvascular Medicine at TBEP, University of Toronto, Toronto, Canada.,3 Heart & Stroke/Richard Lewar Centre of Excellence for Cardiovascular Research, University of Toronto, Toronto, Canada
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Microvascular Dysfunction and Cognitive Impairment. Cell Mol Neurobiol 2016; 36:241-58. [PMID: 26988697 DOI: 10.1007/s10571-015-0308-1] [Citation(s) in RCA: 106] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2015] [Accepted: 11/19/2015] [Indexed: 12/18/2022]
Abstract
The impact of vascular risk factors on cognitive function has garnered much interest in recent years. The appropriate distribution of oxygen, glucose, and other nutrients by the cerebral vasculature is critical for proper cognitive performance. The cerebral microvasculature is a key site of vascular resistance and a preferential target for small vessel disease. While deleterious effects of vascular risk factors on microvascular function are known, the contribution of this dysfunction to cognitive deficits is less clear. In this review, we summarize current evidence for microvascular dysfunction in brain. We highlight effects of select vascular risk factors (hypertension, diabetes, and hyperhomocysteinemia) on the pial and parenchymal circulation. Lastly, we discuss potential links between microvascular disease and cognitive function, highlighting current gaps in our understanding.
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Bonow RH, Silber JR, Enzmann DR, Beauchamp NJ, Ellenbogen RG, Mourad PD. Towards use of MRI-guided ultrasound for treating cerebral vasospasm. J Ther Ultrasound 2016; 4:6. [PMID: 26929821 PMCID: PMC4770693 DOI: 10.1186/s40349-016-0050-2] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2015] [Accepted: 02/19/2016] [Indexed: 12/23/2022] Open
Abstract
Cerebral vasospasm is a major cause of morbidity and mortality in patients with subarachnoid hemorrhage (SAH), causing delayed neurological deficits in as many as one third of cases. Existing therapy targets induction of cerebral vasodilation through use of various drugs and mechanical means, with a range of observed efficacy. Here, we perform a literature review supporting our hypothesis that transcranially delivered ultrasound may have the ability to induce therapeutic cerebral vasodilation and, thus, may one day be used therapeutically in the context of SAH. Prior studies demonstrate that ultrasound can induce vasodilation in both normal and vasoconstricted blood vessels in peripheral tissues, leading to reduced ischemia and cell damage. Among the proposed mechanisms is alteration of several nitric oxide (NO) pathways, where NO is a known vasodilator. While in vivo studies do not point to a specific physical mechanism, results of in vitro studies favor cavitation induction by ultrasound, where the associated shear stresses likely induce NO production. Two papers discussed the effects of ultrasound on the cerebral vasculature. One study applied clinical transcranial Doppler ultrasound to a rodent complete middle cerebral artery occlusion model and found reduced infarct size. A second involved the application of pulsed ultrasound in vitro to murine brain endothelial cells and showed production of a variety of vasodilatory chemicals, including by-products of arachidonic acid metabolism. In sum, nine reviewed studies demonstrated evidence of either cerebrovascular dilation or elaboration of vasodilatory compounds. Of particular interest, all of the reviewed studies used ultrasound capable of transcranial application: pulsed ultrasound, with carrier frequencies ranging between 0.5 and 2.0 MHz, and intensities not substantially above FDA-approved intensity values. We close by discussing potential specific treatment paradigms of SAH and other cerebral ischemic disorders based on MRI-guided transcranial ultrasound.
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Affiliation(s)
- Robert H Bonow
- Department of Neurological Surgery, University of Washington, 325 9th Ave, Box 359924, Seattle, WA 98104 USA
| | - John R Silber
- Department of Neurological Surgery, University of Washington, 325 9th Ave, Box 359924, Seattle, WA 98104 USA
| | - Dieter R Enzmann
- Department of Radiology, University of California Los Angeles, 924 Westwood Blvd. Suite 805, Los Angeles, CA 90024 USA
| | - Norman J Beauchamp
- Department of Radiology, University of Washington, RR-218 Health Science Building, 1959 NE Pacific St, Seattle, WA 98195 USA
| | - Richard G Ellenbogen
- Department of Neurological Surgery, University of Washington, 325 9th Ave, Box 359924, Seattle, WA 98104 USA
| | - Pierre D Mourad
- Department of Neurological Surgery, University of Washington, 325 9th Ave, Box 359924, Seattle, WA 98104 USA ; Department of Radiology, University of Washington, RR-218 Health Science Building, 1959 NE Pacific St, Seattle, WA 98195 USA ; Division of Engineering, University of Washington, 18115 Campus Way NE, Bothell, WA 98011 USA
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CO2 has no therapeutic effect on early microvasospasm after experimental subarachnoid hemorrhage. J Cereb Blood Flow Metab 2014; 34:e1-6. [PMID: 24865999 PMCID: PMC4126102 DOI: 10.1038/jcbfm.2014.96] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/19/2013] [Revised: 03/28/2014] [Accepted: 05/03/2014] [Indexed: 11/09/2022]
Abstract
In addition to delayed vasospasm also early brain injury, which occurs during the first few days after subarachnoid hemorrhage (SAH) when large cerebral arteries are still fully functional, plays an important role for the outcome after SAH. In the current study, we investigated the hypothesis that carbon dioxide (CO2), a strong cerebral vasodilator, has a therapeutic potential against early posthemorrhagic microvasospasm. C57BL/6 mice (n=36) and Sprague-Dawley rats (n=23) were subjected to sham surgery or SAH by filament perforation. The pial microcirculation in the mice was visualized 3 and 24 hours after SAH using intravital fluorescence microscopy. Partial pressure of CO2 (PaCO2) was modulated by hyper- or hypoventilation or by inhalation of 10% CO2. In rats, CO2-mediated changes in cerebral blood flow (CBF) were measured at the same time points using laser Doppler fluxmetry. Increased PaCO2 caused vasodilatation in sham-operated animals. Following SAH, however, cerebral arterioles were nonreactive to CO2. This lack of microvascular CO2 reactivity was accompanied by a complete loss of CO2-induced hyperemia. Our data show that CO2 is not able to dilate spastic microvessels and to increase CBF early after SAH. Future therapeutic approaches will therefore need to address mechanisms beyond CO2.
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Subarachnoid Hemorrhage: a Review of Experimental Studies on the Microcirculation and the Neurovascular Unit. Transl Stroke Res 2014; 5:174-89. [DOI: 10.1007/s12975-014-0323-4] [Citation(s) in RCA: 93] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2013] [Revised: 12/20/2013] [Accepted: 01/03/2014] [Indexed: 11/29/2022]
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Villa F, Iacca C, Molinari AF, Giussani C, Aletti G, Pesenti A, Citerio G. Inhalation versus endovenous sedation in subarachnoid hemorrhage patients: effects on regional cerebral blood flow. Crit Care Med 2012; 40:2797-804. [PMID: 22824929 DOI: 10.1097/ccm.0b013e31825b8bc6] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
OBJECTIVE Isoflurane is a volatile anesthetic that has a vasodilating effect on cerebral vessels producing a cerebral blood flow increase. Furthermore, it has been shown in animal studies that isoflurane, when used as a preconditioning agent, has neuroprotective properties, inducing tolerance to ischemia. However, it is not routinely used in neurointensive care because of the potential increase in intracranial pressure caused by the rise in cerebral blood flow. Nevertheless, subarachnoid hemorrhage patients who are at risk for vasospasm may benefit from an increase in cerebral blood flow. We measured regional cerebral blood flow during intravenous sedation with propofol and during sedation with isoflurane in patients with severe subarachnoid hemorrhage not having intracranial hypertension. DESIGN The study is a crossover, open clinical trial (NCT00830843). SETTING Neurointensive care unit of an academic hospital. PATIENTS Thirteen patients with severe subarachnoid hemorrhage, (median Fisher scale 4), monitored on clinical indication with intracranial pressure device and a thermal diffusion probe for the assessment of regional cerebral blood flow. An intracranial pressure>18 mm Hg was an exclusion criterion. INTERVENTIONS Cerebral and hemodynamic variables were assessed at three steps. Step 1: sedation with propofol 3-4 mg/kg/hr; step 2: after 1 hr of propofol discontinuation and isoflurane 0.8%; step 3: after 1 hr of propofol at the same previous infusion rate. Cerebral perfusion pressure and arterial PCO2 were maintained constant. Mean cerebral artery flow velocity and jugular vein oxygen saturation were measured at the end of each step. MEASUREMENTS AND MAIN RESULTS Regional cerebral blood flow increased significantly during step 2 (39.3±29 mL/100 hg/min) compared to step 1 (20.8±10.7) and step 3 (24.7±8). There was no difference in regional cerebral blood flow comparing step 1 vs. step 3. No significant difference in intracranial pressure, mean cerebral artery transcranial Doppler velocity, PaCO2, cerebral perfusion pressure between the different steps. CONCLUSIONS Isoflurane increases regional cerebral blood flow in comparison to propofol. Intracranial pressure did not change significantly in the population not affected by intracranial hypertension.
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Affiliation(s)
- Federico Villa
- Division of NeuroIntensive Care, Department of Anesthesia and Critical Care, Ospedale San Gerardo, Monza, Italy.
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Erşahin M, Toklu HZ, Akakin D, Yuksel M, Yeğen BC, Sener G. The effects of Nigella sativa against oxidative injury in a rat model of subarachnoid hemorrhage. Acta Neurochir (Wien) 2011; 153:333-41. [PMID: 21072672 DOI: 10.1007/s00701-010-0853-9] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2010] [Accepted: 10/23/2010] [Indexed: 01/10/2023]
Abstract
OBJECTIVE The aim of the study was to investigate the putative neuroprotective effect of Nigella sativa oil (NSO) treatment against subarachnoid hemorrhage (SAH) in rats. METHODS To induce SAH, rats were injected with 0.3 ml blood into their cisterna magna. Male Wistar albino rats were divided as control, vehicle-treated SAH, and NSO-treated (0.2 ml/kg, intraperitoneally) SAH groups. Forty-eight hours after SAH induction, neurological examination scores were recorded and the rats were decapitated. Brain tissue samples were taken for blood brain barrier permeability, brain water content, or determination of malondialdehyde (MDA) and glutathione (GSH) levels, myeloperoxidase (MPO), and Na(+)-K(+)-ATPase activities. RESULTS AND DISCUSSION On the second day of SAH induction, neurological examination scores were increased in SAH groups, while SAH caused significant decreases in brain GSH content and Na(+)-K(+)-ATPase activity, which were accompanied with significant increases in MDA levels and MPO activity. The histological observation showed vasospasm of the basillary artery. On the other hand, NSO treatment markedly improved the neurological scores while all oxidant responses were prevented, implicating that NSO treatment may be of therapeutic use in preventing oxidative stress due to SAH.
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Affiliation(s)
- Mehmet Erşahin
- Department of Neurosurgery, Haydarpasa Numune Education and Research Hospital, Istanbul, Turkey
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Nystoriak MA, O'Connor KP, Sonkusare SK, Brayden JE, Nelson MT, Wellman GC. Fundamental increase in pressure-dependent constriction of brain parenchymal arterioles from subarachnoid hemorrhage model rats due to membrane depolarization. Am J Physiol Heart Circ Physiol 2010; 300:H803-12. [PMID: 21148767 DOI: 10.1152/ajpheart.00760.2010] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Intracerebral (parenchymal) arterioles are morphologically and physiologically unique compared with pial arteries and arterioles. The ability of subarachnoid hemorrhage (SAH) to induce vasospasm in large-diameter pial arteries has been extensively studied, although the contribution of this phenomenon to patient outcome is controversial. Currently, little is known regarding the impact of SAH on parenchymal arterioles, which are critical for regulation of local and global cerebral blood flow. Here diameter, smooth muscle intracellular Ca(2+) concentration ([Ca(2+)](i)), and membrane potential measurements were used to assess the function of intact brain parenchymal arterioles isolated from unoperated (control), sham-operated, and SAH model rats. At low intravascular pressure (5 mmHg), membrane potential and [Ca(2+)](i) were not different in arterioles from control, sham-operated, and SAH animals. However, raising intravascular pressure caused significantly greater membrane potential depolarization, elevation in [Ca(2+)](i), and constriction in SAH arterioles. This SAH-induced increase in [Ca(2+)](i) and tone occurred in the absence of the vascular endothelium and was abolished by the L-type voltage-dependent calcium channel (VDCC) inhibitor nimodipine. Arteriolar [Ca(2+)](i) and tone were not different between groups when smooth muscle membrane potential was adjusted to the same value. Protein and mRNA levels of the L-type VDCC Ca(V)1.2 were similar in parenchymal arterioles isolated from control and SAH animals, suggesting that SAH did not cause VDCC upregulation. We conclude that enhanced parenchymal arteriolar tone after SAH is driven by smooth muscle membrane potential depolarization, leading to increased L-type VDCC-mediated Ca(2+) influx.
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Affiliation(s)
- Matthew A Nystoriak
- Department of Pharmacology, University of Vermont, College of Medicine, Burlington, Vermont 05405-0068, USA
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Kim GS, Amato A, James ML, Britz GW, Zomorodi A, Graffagnino C, Zomorodi M, Olson DM. Continuous and Intermittent CSF Diversion after Subarachnoid Hemorrhage: a Pilot Study. Neurocrit Care 2010; 14:68-72. [DOI: 10.1007/s12028-010-9401-y] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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