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Jammal Salameh L, Bitzenhofer SH, Hanganu-Opatz IL, Dutschmann M, Egger V. Blood pressure pulsations modulate central neuronal activity via mechanosensitive ion channels. Science 2024; 383:eadk8511. [PMID: 38301001 DOI: 10.1126/science.adk8511] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2023] [Accepted: 12/11/2023] [Indexed: 02/03/2024]
Abstract
The transmission of the heartbeat through the cerebral vascular system causes intracranial pressure pulsations. We discovered that arterial pressure pulsations can directly modulate central neuronal activity. In a semi-intact rat brain preparation, vascular pressure pulsations elicited correlated local field oscillations in the olfactory bulb mitral cell layer. These oscillations did not require synaptic transmission but reflected baroreceptive transduction in mitral cells. This transduction was mediated by a fast excitatory mechanosensitive ion channel and modulated neuronal spiking activity. In awake animals, the heartbeat entrained the activity of a subset of olfactory bulb neurons within ~20 milliseconds. Thus, we propose that this fast, intrinsic interoceptive mechanism can modulate perception-for example, during arousal-within the olfactory bulb and possibly across various other brain areas.
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Affiliation(s)
- Luna Jammal Salameh
- Neurophysiology Group, Zoological Institute, Regensburg University, 93040 Regensburg, Germany
| | - Sebastian H Bitzenhofer
- Institute of Developmental Neurophysiology, Center for Molecular Neurobiology, Hamburg Center of Neuroscience, University Medical Center Hamburg-Eppendorf, 20251 Hamburg, Germany
| | - Ileana L Hanganu-Opatz
- Institute of Developmental Neurophysiology, Center for Molecular Neurobiology, Hamburg Center of Neuroscience, University Medical Center Hamburg-Eppendorf, 20251 Hamburg, Germany
| | - Mathias Dutschmann
- Division of Pulmonary, Critical Care, and Sleep Medicine, Department of Medicine, Case Western Reserve University, Cleveland, OH 44106, USA
| | - Veronica Egger
- Neurophysiology Group, Zoological Institute, Regensburg University, 93040 Regensburg, Germany
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2
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Westgate CSJ, Kamp-Jensen C, Israelsen IME, Toft-Bertelsen T, Wardman JH, Jensen CA, Styrishave B, MacAulay N, Jensen RH, Eftekhari S. Acetazolamide and topiramate lower intracranial pressure through differential mechanisms: The effect of acute and chronic administration. Br J Pharmacol 2024; 181:70-86. [PMID: 37553842 DOI: 10.1111/bph.16213] [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: 09/19/2022] [Revised: 05/24/2023] [Accepted: 07/20/2023] [Indexed: 08/10/2023] Open
Abstract
BACKGROUND AND PURPOSE Diseases of raised intracranial pressure (ICP) cause severe morbidity and mortality. Multiple drugs are utilised to lower ICP including acetazolamide and topiramate. However, the evidence for their use is unclear. We aimed to assess the ICP modulatory effects and molecular effects at the choroid plexus (CP) of acetazolamide and topiramate. EXPERIMENTAL APPROACH Female rats were implanted with telemetric ICP probes for physiological, freely moving 24/7 ICP recordings. Randomised cross-over studies were performed, where rats received acute (24 h) high doses of acetazolamide and topiramate, and chronic (10 days) clinically equivalent doses of acetazolamide and topiramate, all via oral gavage. Cerebrospinal fluid (CSF) secretion assays, and RT-qPCR and western blots on in vitro and in vivo CP, were used to investigate drug actions. KEY RESULTS We demonstrate that acetazolamide and topiramate achieved maximal ICP reduction within 120 min of administration, and in combination doubled the ICP reduction over a 24-h period. Chronic administration of acetazolamide or topiramate lowered ICP by 25%. Topiramate decreased CSF secretion by 40%. Chronic topiramate increased the gene expression of Slc12a2 and Slc4a10 and protein expression of the sodium-dependent chloride/bicarbonate exchanger (NCBE), whereas chronic acetazolamide did not affect the expression of assessed genes. CONCLUSIONS AND IMPLICATIONS Acetazolamide and topiramate are effective at lowering ICP at therapeutic levels. We provide the first evidence that topiramate lowers CSF secretion and that acetazolamide and topiramate may lower ICP via distinct molecular mechanisms. Thus, the combination of acetazolamide and topiramate may have utility for treating raised ICP.
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Affiliation(s)
- Connar Stanley James Westgate
- Danish Headache Center, Department of Neurology, Glostrup Research Institute, Rigshospitalet-Glostrup, University of Copenhagen, Copenhagen, Denmark
| | - Christina Kamp-Jensen
- Danish Headache Center, Department of Neurology, Glostrup Research Institute, Rigshospitalet-Glostrup, University of Copenhagen, Copenhagen, Denmark
- Department of Pharmacy, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Ida Marchen Egerod Israelsen
- Danish Headache Center, Department of Neurology, Glostrup Research Institute, Rigshospitalet-Glostrup, University of Copenhagen, Copenhagen, Denmark
| | | | | | - Christian Ahm Jensen
- Danish Headache Center, Department of Neurology, Glostrup Research Institute, Rigshospitalet-Glostrup, University of Copenhagen, Copenhagen, Denmark
- Department of Pharmacy, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Bjarne Styrishave
- Department of Pharmacy, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Nanna MacAulay
- Department of Neuroscience, University of Copenhagen, Copenhagen, Denmark
| | - Rigmor Højland Jensen
- Danish Headache Center, Department of Neurology, Glostrup Research Institute, Rigshospitalet-Glostrup, University of Copenhagen, Copenhagen, Denmark
| | - Sajedeh Eftekhari
- Danish Headache Center, Department of Neurology, Glostrup Research Institute, Rigshospitalet-Glostrup, University of Copenhagen, Copenhagen, Denmark
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3
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Kozler P, Marešová D, Hrachovina M, Pokorný J. Cerebral perfusion pressure and behavior monitoring in freely moving rats. Physiol Res 2023; 72:S543-S549. [PMID: 38165758 PMCID: PMC10861253 DOI: 10.33549/physiolres.935219] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2023] [Accepted: 09/11/2023] [Indexed: 02/01/2024] Open
Abstract
Cerebral perfusion pressure (CPP) is the net pressure gradient that drives oxygen delivery to cerebral tissue. It is the difference between the mean arterial pressure (MAP) and the intracranial pressure (ICP). As CPP is a calculated value, MAP and ICP must be measured simultaneously. In research models, anesthetized and acute monitoring is incapable of providing a realistic picture of the relationship between ICP and MAP under physiological and/or pathophysiological conditions. For long-term monitoring of both pressures, the principle of telemetry can be used. The aim of this study was to map changes in CPP and spontaneous behavior using continuous pressure monitoring and video recording for 7 days under physiological conditions (group C - 8 intact rats) and under altered brain microenvironment induced by brain edema (group WI - 8 rats after water intoxication) and neuroprotection with methylprednisolone - MP (group WI+MP - 8 rats with MP 100 mg/kg b.w. applicated intraperitoneally during WI). The mean CPP values in all three groups were in the range of 40-60 mm Hg. For each group of rats, the percentage of time that the rats spent during the 7 days in movement pattern A (standard movement stereotype) or B (atypical movement) was defined. Even at very low CPP values, the standard movement stereotype (A) clearly dominated over the atypical movement (B) in all rats. There was no significant difference between control and experimental groups. Chronic CPP values with correlated behavioral type may possibly answer the question of whether there is a specific, universal, optimal CPP at all.
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Affiliation(s)
- P Kozler
- Institute of Physiology, First Faculty of Medicine, Charles University, Praha 2, Czech Republic.
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Bordoni L, Thoren AE, Gutiérrez‐Jiménez E, Åbjørsbråten KS, Bjørnstad DM, Tang W, Stern M, Østergaard L, Nagelhus EA, Frische S, Ottersen OP, Enger R. Deletion of aquaporin-4 improves capillary blood flow distribution in brain edema. Glia 2023; 71:2559-2572. [PMID: 37439315 PMCID: PMC10952478 DOI: 10.1002/glia.24439] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2023] [Revised: 06/22/2023] [Accepted: 06/26/2023] [Indexed: 07/14/2023]
Abstract
Brain edema is a feared complication to disorders and insults affecting the brain. It can be fatal if the increase in intracranial pressure is sufficiently large to cause brain herniation. Moreover, accruing evidence suggests that even slight elevations of intracranial pressure have adverse effects, for instance on brain perfusion. The water channel aquaporin-4 (AQP4), densely expressed in perivascular astrocytic endfeet, plays a key role in brain edema formation. Using two-photon microscopy, we have studied AQP4-mediated swelling of astrocytes affects capillary blood flow and intracranial pressure (ICP) in unanesthetized mice using a mild brain edema model. We found improved regulation of capillary blood flow in mice devoid of AQP4, independently of the severity of ICP increase. Furthermore, we found brisk AQP4-dependent astrocytic Ca2+ signals in perivascular endfeet during edema that may play a role in the perturbed capillary blood flow dynamics. The study suggests that astrocytic endfoot swelling and pathological signaling disrupts microvascular flow regulation during brain edema formation.
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Affiliation(s)
- Luca Bordoni
- GliaLab and Letten Centre, Division of Anatomy, Department of Molecular Medicine, Institute of Basic Medical SciencesUniversity of OsloOsloNorway
- Department of BiomedicineAarhus UniversityAarhusDenmark
| | - Anna E. Thoren
- GliaLab and Letten Centre, Division of Anatomy, Department of Molecular Medicine, Institute of Basic Medical SciencesUniversity of OsloOsloNorway
| | - Eugenio Gutiérrez‐Jiménez
- Center of Functionally Integrative Neuroscience (CFIN), Department of Clinical MedicineAarhus UniversityAarhusDenmark
| | - Knut S. Åbjørsbråten
- GliaLab and Letten Centre, Division of Anatomy, Department of Molecular Medicine, Institute of Basic Medical SciencesUniversity of OsloOsloNorway
| | - Daniel M. Bjørnstad
- GliaLab and Letten Centre, Division of Anatomy, Department of Molecular Medicine, Institute of Basic Medical SciencesUniversity of OsloOsloNorway
| | - Wannan Tang
- GliaLab and Letten Centre, Division of Anatomy, Department of Molecular Medicine, Institute of Basic Medical SciencesUniversity of OsloOsloNorway
- Department of Clinical and Molecular MedicineNorwegian University of Science and TechnologyTrondheimNorway
- Department of Neurology, NeuroclinicSt. Olavs HospitalTrondheimNorway
| | - Mette Stern
- Department of BiomedicineAarhus UniversityAarhusDenmark
| | - Leif Østergaard
- Center of Functionally Integrative Neuroscience (CFIN), Department of Clinical MedicineAarhus UniversityAarhusDenmark
- Department of NeuroradiologyAarhus University HospitalAarhusDenmark
| | - Erlend A. Nagelhus
- GliaLab and Letten Centre, Division of Anatomy, Department of Molecular Medicine, Institute of Basic Medical SciencesUniversity of OsloOsloNorway
| | | | - Ole P. Ottersen
- GliaLab and Letten Centre, Division of Anatomy, Department of Molecular Medicine, Institute of Basic Medical SciencesUniversity of OsloOsloNorway
| | - Rune Enger
- GliaLab and Letten Centre, Division of Anatomy, Department of Molecular Medicine, Institute of Basic Medical SciencesUniversity of OsloOsloNorway
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Israelsen IME, Westgate CSJ, Kamp-Jensen C, Jensen RH, Eftekhari S. Effects of caffeine on intracranial pressure and pain perception in freely moving rats. Headache 2023; 63:1220-1231. [PMID: 37796087 DOI: 10.1111/head.14634] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2023] [Revised: 08/28/2023] [Accepted: 08/29/2023] [Indexed: 10/06/2023]
Abstract
OBJECTIVE Caffeine, a non-selective adenosine receptor (AR) antagonist, is the most consumed psychostimulant in the world. Caffeine has been suggested to regulate cerebrospinal fluid secretion and is known both to alleviate and to trigger headache; however, its effect on the regulation of intracranial pressure (ICP) is not known. Therefore, we aimed to investigate the effects of caffeine on ICP and nociceptive responses. METHODS Female Sprague-Dawley rats were implanted with a novel telemetric device for continuous ICP recordings, which allowed for continuous recordings in freely moving rats. A single dose of caffeine (30 or 120 mg/kg intraperitoneally) was given. In a second group (non-implanted), the acute effects of 30 mg/kg caffeine on periorbital threshold using Von Frey testing and spontaneous behavior were utilized using an automated behavioral registration platform (Laboratory, Animal, Behavior, Observation, Registration and Analysis System) in a randomized cross-over study. Quantitative polymerase chain reaction and immunofluorescence were used to localize ARs in the choroid plexus. RESULTS A single dose of 30 mg/kg caffeine lowered the ICP by 35% at 165 min after administration (saline: 0.16 ± 0.9 vs caffeine: -1.18 ± 0.9 ΔmmHg, p = 0.0098) and lasted up to 12 h. Administration of 120 mg/kg caffeine showed a faster onset of decrease in ICP within 15 min by 50% (p = 0.0018) and lasted up to 12 h. The periorbital pain thresholds were higher after 1 h (saline: 224.6 ± 15.1 vs caffeine: 289.5 ± 8.7 g, p = 0.005) and lasted up to 5 h. Caffeine-treated rats had increased locomotor activity, speed, and changed grooming behavior. Expression of AR1 was found in the choroid plexus. CONCLUSIONS This study demonstrates that caffeine has a lowering effect on ICP as an acute treatment. Interestingly, caffeine acutely caused an increased response in cephalic thresholds supporting hypoalgesic effects. Future studies investigating the beneficial effects of caffeine for elevated ICP are warranted.
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Affiliation(s)
- Ida Marchen Egerod Israelsen
- Department of Neurology, Danish Headache Center, Glostrup Research Institute, Rigshospitalet-Glostrup, University of Copenhagen, Glostrup, Denmark
| | - Connar Stanley James Westgate
- Department of Neurology, Danish Headache Center, Glostrup Research Institute, Rigshospitalet-Glostrup, University of Copenhagen, Glostrup, Denmark
| | - Christina Kamp-Jensen
- Department of Neurology, Danish Headache Center, Glostrup Research Institute, Rigshospitalet-Glostrup, University of Copenhagen, Glostrup, Denmark
| | - Rigmor H Jensen
- Department of Neurology, Danish Headache Center, Glostrup Research Institute, Rigshospitalet-Glostrup, University of Copenhagen, Glostrup, Denmark
| | - Sajedeh Eftekhari
- Department of Neurology, Danish Headache Center, Glostrup Research Institute, Rigshospitalet-Glostrup, University of Copenhagen, Glostrup, Denmark
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Steffensen AB, Edelbo BL, Barbuskaite D, Andreassen SN, Olsen MH, Møller K, MacAulay N. Nocturnal increase in cerebrospinal fluid secretion as a circadian regulator of intracranial pressure. Fluids Barriers CNS 2023; 20:49. [PMID: 37353833 DOI: 10.1186/s12987-023-00451-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2023] [Accepted: 06/06/2023] [Indexed: 06/25/2023] Open
Abstract
BACKGROUND It is crucial to maintain the intracranial pressure (ICP) within the physiological range to ensure proper brain function. The ICP may fluctuate during the light-dark phase cycle, complicating diagnosis and treatment choice in patients with pressure-related disorders. Such ICP fluctuations may originate in circadian or sleep-wake cycle-mediated modulation of cerebrospinal fluid (CSF) flow dynamics, which in addition could support diurnal regulation of brain waste clearance. METHODS ICP was monitored continuously in patients who underwent placement of an external ventricular drain (EVD) and by telemetric monitoring in experimental rats. CSF was collected via the EVD in patients and the rodent CSF secretion rate determined by in vivo experimentation. Rodent choroid plexus transporter transcripts were quantified with RNAseq and transport activity with ex vivo isotope transport assays. RESULTS We demonstrated that ICP increases by 30% in the dark phase in both species, independently of vascular parameters. This increase aligns with elevated CSF collection in patients (12%) and CSF production rate in rats (20%), the latter obtained with the ventriculo-cisternal perfusion assay. The dark-phase increase in CSF secretion in rats was, in part, assigned to increased transport activity of the choroid plexus Na+,K+,2Cl- cotransporter (NKCC1), which is implicated in CSF secretion by this tissue. CONCLUSION CSF secretion, and thus ICP, increases in the dark phase in humans and rats, irrespective of their diurnal/nocturnal activity preference, in part due to altered choroid plexus transport activity in the rat. Our findings suggest that CSF dynamics are modulated by the circadian rhythm, rather than merely sleep itself.
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Affiliation(s)
- Annette Buur Steffensen
- Faculty of Health and Medical Sciences, Department of Neuroscience, University of Copenhagen, Blegdamsvej 3, DK-2200, Copenhagen N, Denmark
| | - Beatriche Louise Edelbo
- Faculty of Health and Medical Sciences, Department of Neuroscience, University of Copenhagen, Blegdamsvej 3, DK-2200, Copenhagen N, Denmark
| | - Dagne Barbuskaite
- Faculty of Health and Medical Sciences, Department of Neuroscience, University of Copenhagen, Blegdamsvej 3, DK-2200, Copenhagen N, Denmark
| | - Søren Norge Andreassen
- Faculty of Health and Medical Sciences, Department of Neuroscience, University of Copenhagen, Blegdamsvej 3, DK-2200, Copenhagen N, Denmark
| | - Markus Harboe Olsen
- Department of Neuroanaesthesiology, The Neuroscience Center, Copenhagen University Hospital-Rigshospitalet, Copenhagen, Denmark
- Department of Clinical Medicine, University of Copenhagen, Copenhagen, Denmark
| | - Kirsten Møller
- Department of Neuroanaesthesiology, The Neuroscience Center, Copenhagen University Hospital-Rigshospitalet, Copenhagen, Denmark
- Department of Clinical Medicine, University of Copenhagen, Copenhagen, Denmark
| | - Nanna MacAulay
- Faculty of Health and Medical Sciences, Department of Neuroscience, University of Copenhagen, Blegdamsvej 3, DK-2200, Copenhagen N, Denmark.
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7
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Westgate CSJ, Israelsen IME, Kamp-Jensen C, Jensen RH, Eftekhari S. Glucocorticoids modify intracranial pressure in freely moving rats. Fluids Barriers CNS 2023; 20:35. [PMID: 37231507 DOI: 10.1186/s12987-023-00439-y] [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: 03/17/2023] [Accepted: 05/06/2023] [Indexed: 05/27/2023] Open
Abstract
BACKGROUND Glucocorticoids (GCs) are widely prescribed for a variety of inflammatory diseases, but they are also used to treat raised intracranial pressure (ICP) caused by trauma or oedema. However, it is unclear if GCs independently modulate ICP and if GCs are involved in normal ICP regulation. In this study, we aimed to assess the ICP modulatory effects of GCs and their molecular consequences on choroid plexus (CP). METHODS Adult female rats were implanted with telemetric ICP probes for physiological, continuous ICP recordings in a freely moving setup. Rats received prednisolone or vehicle via oral gavage in a randomized acute (24 h) ICP study. In a subsequent study rats received corticosterone or vehicle in drinking water for a 4-week chronic ICP study. CP were removed, and the expression of genes associated with cerebrospinal fluid secretion were assessed. RESULTS A single prednisolone dose reduced ICP by up to 48% (P < 0.0001), where ICP was reduced within 7 h and was maintained for at least 14 h. Prednisolone increases ICP spiking (P = 0.0075) while not altering ICP waveforms. Chronic corticosterone reduces ICP by up to 44%, where ICP was lower for the entirety of the 4-week ICP recording period (P = 0.0064). ICP daily periodicity was not altered by corticosterone. Corticosterone ICP reduction was not accompanied by ICP spike differences or alteration in ICP spike periodicity. Chronic corticosterone treatment had modest effects on CP gene expression, lowering the expression of Car2 at CP (P = 0.047). CONCLUSIONS GCs reduce ICP in both the acute and chronic setting to a similar degree. Moreover, GCs did not modify the diurnal rhythm of ICP, suggesting the diurnal variation of ICP periodicity is not under explicit control of GCs. ICP disturbances should be considered a consequence of GC therapy. Based on these experiments, GCs may have broader ICP therapeutic uses, but side effects must be taken into consideration.
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Affiliation(s)
- Connar Stanley James Westgate
- Danish Headache Center, Dept of Neurology, Rigshospitalet-Glostrup, Glostrup Research Institute, University of Copenhagen, Glostrup, Denmark
| | - Ida Marchen Egerod Israelsen
- Danish Headache Center, Dept of Neurology, Rigshospitalet-Glostrup, Glostrup Research Institute, University of Copenhagen, Glostrup, Denmark
| | - Christina Kamp-Jensen
- Danish Headache Center, Dept of Neurology, Rigshospitalet-Glostrup, Glostrup Research Institute, University of Copenhagen, Glostrup, Denmark
| | - Rigmor Højland Jensen
- Danish Headache Center, Dept of Neurology, Rigshospitalet-Glostrup, Glostrup Research Institute, University of Copenhagen, Glostrup, Denmark
| | - Sajedeh Eftekhari
- Danish Headache Center, Dept of Neurology, Rigshospitalet-Glostrup, Glostrup Research Institute, University of Copenhagen, Glostrup, Denmark.
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Bitanihirwe BKY, Lizano P, Woo TUW. Deconstructing the functional neuroanatomy of the choroid plexus: an ontogenetic perspective for studying neurodevelopmental and neuropsychiatric disorders. Mol Psychiatry 2022; 27:3573-3582. [PMID: 35618887 PMCID: PMC9133821 DOI: 10.1038/s41380-022-01623-6] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/04/2022] [Revised: 04/15/2022] [Accepted: 05/11/2022] [Indexed: 02/08/2023]
Abstract
The choroid plexus (CP) is a delicate and highly vascularized structure in the brain comprised of a dense network of fenestrated capillary loops that help in the synthesis, secretion and circulation of cerebrospinal fluid (CSF). This unique neuroanatomical structure is comprised of arachnoid villi stemming from frond-like surface projections-that protrude into the lumen of the four cerebral ventricles-providing a key source of nutrients to the brain parenchyma in addition to serving as a 'sink' for central nervous system metabolic waste. In fact, the functions of the CP are often described as being analogous to those of the liver and kidney. Beyond forming a barrier/interface between the blood and CSF compartments, the CP has been identified as a modulator of leukocyte trafficking, inflammation, cognition, circadian rhythm and the gut brain-axis. In recent years, advances in molecular biology techniques and neuroimaging along with the use of sophisticated animal models have played an integral role in shaping our understanding of how the CP-CSF system changes in relation to the maturation of neural circuits during critical periods of brain development. In this article we provide an ontogenetic perspective of the CP and review the experimental evidence implicating this structure in the pathophysiology of neurodevelopmental and neuropsychiatric disorders.
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Affiliation(s)
- Byron K Y Bitanihirwe
- Humanitarian and Conflict Response Institute, University of Manchester, Manchester, UK.
| | - Paulo Lizano
- Department of Psychiatry, Harvard Medical School, Boston, MA, USA
- Department of Psychiatry, Beth Israel Deaconess Medical Center, Boston, MA, USA
- Translational Neuroscience Division, Beth Israel Deaconess Medical Center, Boston, MA, USA
| | - Tsung-Ung W Woo
- Department of Psychiatry, Harvard Medical School, Boston, MA, USA
- Program in Molecular Neuropathology, McLean Hospital, Belmont, MA, USA
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Young BA, Cramberg MJ. Treadmill locomotion in the American alligator (Alligator mississippiensis) produces dynamic changes in intracranial cerebrospinal fluid pressure. Sci Rep 2022; 12:11826. [PMID: 35821242 PMCID: PMC9276781 DOI: 10.1038/s41598-022-15918-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2022] [Accepted: 07/01/2022] [Indexed: 11/09/2022] Open
Abstract
To examine the influence of movement on cerebrospinal fluid (CSF) dynamics, intracranial subdural pressure recordings were taken from sub-adult alligators (Alligator mississippiensis) locomoting on a treadmill. Pressure recordings documenting the cardiac, ventilatory, and barostatic influences on the CSF were in good agreement with previous studies. During locomotion the CSF exhibits sinusoidal patterns of pressure change that spanned a mean amplitude of 56 mm Hg, some 16 × the amplitude of the cardiac-linked pulsations. These sinusoidal CSF pulsations were closely linked to the locomotor kinematics, particularly the lateral oscillations of the alligator's head. Data recorded from the freely moving alligators suggest that fluid inertia, body cavity pressures, and likely other factors all influence the CSF pressure. The clear relationship between movement and CSF pressure described in this study suggests that the paucity of studies examining human CSF dynamics during movement should be addressed.
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Affiliation(s)
- Bruce A Young
- Department of Anatomy, Kirksville College of Osteopathic Medicine, A.T. Still University, Kirksville, MO, 63501, USA.
| | - Michael J Cramberg
- Department of Anatomy, Kirksville College of Osteopathic Medicine, A.T. Still University, Kirksville, MO, 63501, USA
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10
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Westgate CSJ, Hagen SM, Israelsen IME, Hamann S, Jensen RH, Eftekhari S. The impact of obesity-related raised intracranial pressure in rodents. Sci Rep 2022; 12:9102. [PMID: 35650312 PMCID: PMC9160066 DOI: 10.1038/s41598-022-13181-6] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2021] [Accepted: 05/06/2022] [Indexed: 12/31/2022] Open
Abstract
Elevated intracranial pressure (ICP) is observed in many brain disorders. Obesity has been linked to ICP pathogenesis in disorders such as idiopathic intracranial pressure (IIH). We investigated the effect of diet induced obesity (DIO) on ICP and clinically relevant sequelae. Rats were fed either a control or high fat diet. Following weight gain long term ICP, headache behavior, body composition and retinal outcome were examined. Post-hoc analysis of retinal histology and molecular analysis of choroid plexus and trigeminal ganglion (TG) were performed. DIO rats demonstrated raised ICP by 55% which correlated with the abdominal fat percentage and increased non-respiratory slow waves, suggestive of altered cerebral compliance. Concurrently, DIO rats demonstrated a specific cephalic cutaneous allodynia which negatively correlated with the abdominal fat percentage. This sensitivity was associated with increased expression of headache markers in TG. Additionally, DIO rats had increased retinal nerve fiber layer thickness in vivo associated with raised ICP with a subsequent post-hoc demonstration of neuroretinal degeneration. This study demonstrates for the first time that DIO leads to raised ICP and subsequent clinically relevant symptom development. This novel model of non-traumatic raised ICP could expand the knowledge regarding disorders with elevated ICP such as IIH.
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Affiliation(s)
- Connar Stanley James Westgate
- Department of Neurology, Danish Headache Center, Glostrup Research Institute, Rigshospitalet-Glostrup, University of Copenhagen, Nordstjernevej 42, 2600, Copenhagen, Denmark
| | - Snorre Malm Hagen
- Department of Neurology, Danish Headache Center, Glostrup Research Institute, Rigshospitalet-Glostrup, University of Copenhagen, Nordstjernevej 42, 2600, Copenhagen, Denmark
- Department of Ophthalmology, Rigshospitalet-Glostrup, University of Copenhagen, Copenhagen, Denmark
| | - Ida Marchen Egerod Israelsen
- Department of Neurology, Danish Headache Center, Glostrup Research Institute, Rigshospitalet-Glostrup, University of Copenhagen, Nordstjernevej 42, 2600, Copenhagen, Denmark
| | - Steffen Hamann
- Department of Ophthalmology, Rigshospitalet-Glostrup, University of Copenhagen, Copenhagen, Denmark
| | - Rigmor Højland Jensen
- Department of Neurology, Danish Headache Center, Glostrup Research Institute, Rigshospitalet-Glostrup, University of Copenhagen, Nordstjernevej 42, 2600, Copenhagen, Denmark
| | - Sajedeh Eftekhari
- Department of Neurology, Danish Headache Center, Glostrup Research Institute, Rigshospitalet-Glostrup, University of Copenhagen, Nordstjernevej 42, 2600, Copenhagen, Denmark.
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11
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Hagen SM, Eftekhari S, Hamann S, Juhler M, Jensen RH. Intracranial pressure and optic disc changes in a rat model of obstructive hydrocephalus. BMC Neurosci 2022; 23:29. [PMID: 35606718 PMCID: PMC9128145 DOI: 10.1186/s12868-022-00716-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2021] [Accepted: 05/11/2022] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND The kaolin induced obstructive hydrocephalus (OHC) model is well known for its ability to increase intracranial pressure (ICP) in experimental animals. Papilledema (PE) which is a predominant hallmark of elevated ICP in the clinic has not yet been studied in this model using high-resolution digital fundus microscopy. Further, the long-term effect on ICP and optic nerve head changes have not been fully demonstrated. In this study we aimed to monitor epidural ICP after induction of OHC and to examine changes in the optic disc. In addition, we validated epidural ICP to intraventricular ICP in this disease model. METHOD Thirteen male Sprague-Dawley rats received an injection into the cisterna magna containing either kaolin-Ringer's lactate suspension (n = 8) or an equal amount of Ringer's lactate solution (n = 5). Epidural ICP was recorded post-operatively, and then continuously overnight and followed up after 1 week. The final epidural ICP value after 1 week was confirmed with simultaneous ventricular ICP measurement. Optic disc photos (ODP) were obtained preoperatively at baseline and after one week and were assessed for papilledema. RESULTS All animals injected with kaolin developed OHC and had significant higher epidural ICP (15.49 ± 2.47 mmHg) compared to control animals (5.81 ± 1.33 mmHg) on day 1 (p < 0.0001). After 1 week, the epidural ICP values were subsided to normal range in hydrocephalus animals and there was no significant difference in epidural ICP between the groups. Epidural ICP after 1 week correlated with the ventricular ICP with a Pearson's r = 0.89 (p < 0.0001). ODPs from both groups showed no signs of acute papilledema, but 5 out of 8 (62.5%) of the hydrocephalus animals were identified with peripapillary changes. CONCLUSIONS We demonstrated that the raised ICP at day 1 in the hydrocephalus animals was completely normalized within 1 week and that epidural ICP measurements are valid method in this model. No acute papilledema was identified in the hydrocephalus animals, but the peripapillary changes indicate a potential gliosis formation or an early state of a growing papilledema in the context of lateral ventricle dilation and increased ICP.
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Affiliation(s)
- Snorre Malm Hagen
- Department of Ophthalmology, Rigshospitalet, University of Copenhagen, Valdemar Hansens Vej 13, 2600, Glostrup, Denmark.
- Danish Headache Center, Department of Neurology, Glostrup Research Institute, Rigshospitalet, University of Copenhagen, Nordstjernevej 42, 2600, Glostrup, Denmark.
| | - Sajedeh Eftekhari
- Danish Headache Center, Department of Neurology, Glostrup Research Institute, Rigshospitalet, University of Copenhagen, Nordstjernevej 42, 2600, Glostrup, Denmark.
| | - Steffen Hamann
- Department of Ophthalmology, Rigshospitalet, University of Copenhagen, Valdemar Hansens Vej 13, 2600, Glostrup, Denmark.
| | - Marianne Juhler
- Department of Neurosurgery, Rigshospitalet, University of Copenhagen, Blegdamsvej 9, 2100, Copenhagen Ø, Denmark.
| | - Rigmor H Jensen
- Danish Headache Center, Department of Neurology, Glostrup Research Institute, Rigshospitalet, University of Copenhagen, Nordstjernevej 42, 2600, Glostrup, Denmark.
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Abstract
The brain harbors a unique ability to, figuratively speaking, shift its gears. During wakefulness, the brain is geared fully toward processing information and behaving, while homeostatic functions predominate during sleep. The blood-brain barrier establishes a stable environment that is optimal for neuronal function, yet the barrier imposes a physiological problem; transcapillary filtration that forms extracellular fluid in other organs is reduced to a minimum in brain. Consequently, the brain depends on a special fluid [the cerebrospinal fluid (CSF)] that is flushed into brain along the unique perivascular spaces created by astrocytic vascular endfeet. We describe this pathway, coined the term glymphatic system, based on its dependency on astrocytic vascular endfeet and their adluminal expression of aquaporin-4 water channels facing toward CSF-filled perivascular spaces. Glymphatic clearance of potentially harmful metabolic or protein waste products, such as amyloid-β, is primarily active during sleep, when its physiological drivers, the cardiac cycle, respiration, and slow vasomotion, together efficiently propel CSF inflow along periarterial spaces. The brain's extracellular space contains an abundance of proteoglycans and hyaluronan, which provide a low-resistance hydraulic conduit that rapidly can expand and shrink during the sleep-wake cycle. We describe this unique fluid system of the brain, which meets the brain's requisites to maintain homeostasis similar to peripheral organs, considering the blood-brain-barrier and the paths for formation and egress of the CSF.
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Affiliation(s)
- Martin Kaag Rasmussen
- Center for Translational Neuromedicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Humberto Mestre
- Center for Translational Neuromedicine, University of Rochester Medical Center, Rochester, New York
| | - Maiken Nedergaard
- Center for Translational Neuromedicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
- Center for Translational Neuromedicine, University of Rochester Medical Center, Rochester, New York
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Shah J, Quinkert C, Collar B, Williams M, Biggs E, Irazoqui P. A Highly Miniaturized, Chronically Implanted ASIC for Electrical Nerve Stimulation. IEEE TRANSACTIONS ON BIOMEDICAL CIRCUITS AND SYSTEMS 2022; 16:233-243. [PMID: 35201991 PMCID: PMC9195150 DOI: 10.1109/tbcas.2022.3153282] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
We present a wireless, fully implantable device for electrical stimulation of peripheral nerves consisting of a powering coil, a tuning network, a Zener diode, selectable stimulation parameters, and a stimulator IC, all encapsulated in biocompatible silicone. A wireless RF signal at 13.56 MHz powers the implant through the on-chip rectifier. The ASIC, designed in TSMC's 180 nm MS RF G process, occupies an area of less than 1.2 mm2. The IC enables externally selectable current-controlled stimulation through an on-chip read-only memory with a wide range of 32 stimulation parameters (90-750 µA amplitude, 100 µs or 1 ms pulse width, 15 or 50 Hz frequency). The IC generates the constant current waveform using an 8-bit binary weighted DAC and an H-Bridge. At the most power-hungry stimulation parameter, the average power consumption during a stimulus pulse is 2.6 mW with a power transfer efficiency of ∼5.2%. In addition to benchtop and acute testing, we chronically implanted two versions of the device (a design with leads and a leadless design) on two rats' sciatic nerves to verify the long-term efficacy of the IC and the full system. The leadless device had the following dimensions: height of 0.45 cm, major axis of 1.85 cm, and minor axis of 1.34 cm, with similar dimensions for the device with leads. Both devices were implanted and worked for experiments lasting from 21-90 days. To the best of our knowledge, the fabricated IC is the smallest constant-current stimulator that has been tested chronically.
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Zhang Q, Turner KL, Gheres KW, Hossain MS, Drew PJ. Behavioral and physiological monitoring for awake neurovascular coupling experiments: a how-to guide. NEUROPHOTONICS 2022; 9:021905. [PMID: 35639834 PMCID: PMC8802326 DOI: 10.1117/1.nph.9.2.021905] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/15/2021] [Accepted: 12/28/2021] [Indexed: 06/15/2023]
Abstract
Significance: Functional brain imaging in awake animal models is a popular and powerful technique that allows the investigation of neurovascular coupling (NVC) under physiological conditions. However, ubiquitous facial and body motions (fidgeting) are prime drivers of spontaneous fluctuations in neural and hemodynamic signals. During periods without movement, animals can rapidly transition into sleep, and the hemodynamic signals tied to arousal state changes can be several times larger than sensory-evoked responses. Given the outsized influence of facial and body motions and arousal signals in neural and hemodynamic signals, it is imperative to detect and monitor these events in experiments with un-anesthetized animals. Aim: To cover the importance of monitoring behavioral state in imaging experiments using un-anesthetized rodents, and describe how to incorporate detailed behavioral and physiological measurements in imaging experiments. Approach: We review the effects of movements and sleep-related signals (heart rate, respiration rate, electromyography, intracranial pressure, whisking, and other body movements) on brain hemodynamics and electrophysiological signals, with a focus on head-fixed experimental setup. We summarize the measurement methods currently used in animal models for detection of those behaviors and arousal changes. We then provide a guide on how to incorporate this measurements with functional brain imaging and electrophysiology measurements. Results: We provide a how-to guide on monitoring and interpreting a variety of physiological signals and their applications to NVC experiments in awake behaving mice. Conclusion: This guide facilitates the application of neuroimaging in awake animal models and provides neuroscientists with a standard approach for monitoring behavior and other associated physiological parameters in head-fixed animals.
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Affiliation(s)
- Qingguang Zhang
- The Pennsylvania State University, Center for Neural Engineering, Department of Engineering Science and Mechanics, University Park, Pennsylvania, United States
| | - Kevin L. Turner
- The Pennsylvania State University, Department of Biomedical Engineering, University Park, Pennsylvania, United States
| | - Kyle W. Gheres
- The Pennsylvania State University, Graduate Program in Molecular Cellular and Integrative Biosciences, University Park, Pennsylvania, United States
| | - Md Shakhawat Hossain
- The Pennsylvania State University, Department of Biomedical Engineering, University Park, Pennsylvania, United States
| | - Patrick J. Drew
- The Pennsylvania State University, Center for Neural Engineering, Department of Engineering Science and Mechanics, University Park, Pennsylvania, United States
- The Pennsylvania State University, Department of Biomedical Engineering, University Park, Pennsylvania, United States
- The Pennsylvania State University, Department of Neurosurgery, University Park, Pennsylvania, United States
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Li Y, He J, Zhou J, Li Z, Liu L, Hu S, Guo B, Wang W. Conductive photothermal non-swelling nanocomposite hydrogel patch accelerating bone defect repair. Biomater Sci 2022; 10:1326-1341. [DOI: 10.1039/d1bm01937f] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Bone defect repair is one of the most common issue in clinic. Developmental multifunctional scaffolds have become a promising strategy to effectively promote bone defect repair. Here, a series of...
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Khasawneh AH, Alexandra PC, Zajciw PA, Harris CA. A preliminary exploration of acute intracranial pressure-cerebrospinal fluid production relationships in experimental hydrocephalus. Brain Circ 2020; 6:200-207. [PMID: 33210046 PMCID: PMC7646388 DOI: 10.4103/bc.bc_42_20] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2020] [Revised: 09/10/2020] [Accepted: 09/13/2020] [Indexed: 11/04/2022] Open
Abstract
CONTEXT By occluding the fourth ventricle simultaneously obtaining telemetric data on intracranial pressure (ICP) and cerebrospinal fluid (CSF) production, the authors of this study investigate a variety of physiologic parameters in cases of experimental hydrocephalus. AIMS The aim of this study is to provide a new context on the disrupted homeostasis in hydrocephalus and guide toward improved treatment based on multiple physiological parameters. MATERIALS AND METHODS Hydrocephalus was induced in ten 21-day-old Sprague-Dawley rats by blocking the flow of CSF to the fourth ventricle with kaolin. Ten days post induction, when physical signs of ventriculomegaly reached Evan's ratio (ER) of ≥0.46, CSF flow and ICP were measured while manipulating body position (0°, 45°, 90°) and heart rate. RESULTS In hydrocephalic animals (ER ≥0.46), we found a near-steady average acute ICP (13.638 ± 2.331) compared to age-matched controls (ER <0.30) (13.068 ± 8.781), whose ICP fluctuated with the position. Hydrocephalic and controls exhibited an insignificant degree of parabolic shifts in CSF production when body position was changed from prone to 90° and again when moved back to the prone position, a trend more noteworthy in controls (P = 0.1322 and 0.2772). A Pearson's Correlation found CSF production and ICP to be correlated at baseline 0° posture (P = 0.05) in the control group, but not the hydrocephalic group. Weight appeared to play a role when animals were held at 90°. No significant changes in ICP or CSF flow patterns were observed when the heart rate was increased within either group. CONCLUSIONS These preliminary findings suggest that our standard assumptions of posture-dependent changes in ICP created using data from physiologic data may be inaccurate in the hydrocephalic patient, and thus describe a need to further explore these relationships.
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Affiliation(s)
- Ahmad H Khasawneh
- Department of Chemical Engineering, Wayne State University, Detroit, Michigan, USA
| | - Petroj C Alexandra
- Department of Chemical Engineering, Wayne State University, Detroit, Michigan, USA
| | - Paul A Zajciw
- Department of Chemical Engineering, Wayne State University, Detroit, Michigan, USA
| | - Carolyn A Harris
- Department of Chemical Engineering, Wayne State University, Detroit, Michigan, USA.,Department of Biomedical Engineering, Wayne State University, Detroit, Michigan, USA.,Department of Neurosurgery, Wayne State University, Detroit, Michigan, USA
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Echagarruga CT, Gheres KW, Norwood JN, Drew PJ. nNOS-expressing interneurons control basal and behaviorally evoked arterial dilation in somatosensory cortex of mice. eLife 2020; 9:e60533. [PMID: 33016877 PMCID: PMC7556878 DOI: 10.7554/elife.60533] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2020] [Accepted: 10/02/2020] [Indexed: 12/19/2022] Open
Abstract
Cortical neural activity is coupled to local arterial diameter and blood flow. However, which neurons control the dynamics of cerebral arteries is not well understood. We dissected the cellular mechanisms controlling the basal diameter and evoked dilation in cortical arteries in awake, head-fixed mice. Locomotion drove robust arterial dilation, increases in gamma band power in the local field potential (LFP), and increases calcium signals in pyramidal and neuronal nitric oxide synthase (nNOS)-expressing neurons. Chemogenetic or pharmocological modulation of overall neural activity up or down caused corresponding increases or decreases in basal arterial diameter. Modulation of pyramidal neuron activity alone had little effect on basal or evoked arterial dilation, despite pronounced changes in the LFP. Modulation of the activity of nNOS-expressing neurons drove changes in the basal and evoked arterial diameter without corresponding changes in population neural activity.
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Affiliation(s)
| | - Kyle W Gheres
- Molecular, Cellular, and Integrative Biology Graduate Program, Pennsylvania State UniversityUniversity ParkUnited States
| | - Jordan N Norwood
- Cell and Developmental Biology Graduate Program, Pennsylvania State UniversityUniversity ParkUnited States
| | - Patrick J Drew
- Bioengineering Graduate Program, Pennsylvania State UniversityUniversity ParkUnited States
- Molecular, Cellular, and Integrative Biology Graduate Program, Pennsylvania State UniversityUniversity ParkUnited States
- Cell and Developmental Biology Graduate Program, Pennsylvania State UniversityUniversity ParkUnited States
- Departments of Engineering Science and Mechanics, Biomedical Engineering, and Neurosurgery, Pennsylvania State UniversityUniversity ParkUnited States
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