Evidence for a Predominant Intrinsic Sympathetic Control of Cerebral Blood Flow Alterations in an Animal Model of Cerebr
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ORIGINAL ARTICLE
Evidence for a Predominant Intrinsic Sympathetic Control of Cerebral Blood Flow Alterations in an Animal Model of Cerebral Arteriovenous Malformation Carsten Stüer & Toshiki Ikeda & Michael Stoffel & Gerd Luippold & Carlo Schaller & Bernhard Meyer
Received: 14 December 2009 / Revised: 18 February 2010 / Accepted: 22 March 2010 / Published online: 13 April 2010 # Springer Science+Business Media, LLC 2010
Abstract In terms of neurogenic cerebral blood flow (CBF) control, the activity of the sympathetic nervous system (SNS) has a regulating effect. The impact of a manipulation of both the peripheral (via the perivascular sympathetic net) and central components (via the intracortical noradrenergic terminals originating from the locus coeruleus) on CBF—and especially on hyperperfusion syndromes—is unclear. To test the specific patterns following such alterations, cortical oxygen saturation (rSO2), regional CBF (rCBF), and cortical interstitial norepinephrine (NE) concentrations were measured. Twelve weeks after either the creation of an extracranial AV fistula or sham operation, 80 male Sprague–Dawley rats underwent one of the following procedures: (1) no SNS manipulation, (2) peripheral SNS inhibition via bilateral
Disclosure/Conflict of interest This work was supported by the German Research Council (DFG grant ME 1082/1-1). None of the authors has any competing financial interest. C. Stüer (*) : M. Stoffel : B. Meyer Department of Neurosurgery, Klinikum rechts der Isar, Technische Universität München, Ismaninger Strasse 22, 81675 Munich, Germany e-mail: [email protected] C. Stüer : T. Ikeda : M. Stoffel : C. Schaller : B. Meyer Department of Neurosurgery, Rheinische Friedrich-Wilhelms-Universität Bonn, Bonn, Germany G. Luippold Institute of Pharmacology, Eberhard Karls-Universität Tübingen, Tübingen, Germany C. Schaller Service de Neurochirurgie, Hôpitaux Universitaires de Genève, Genève, Switzerland
sympathectomy, (3) central SNS inhibition via the neurotoxin DSP-4, or (4) complete SNS inhibition. Norepinephrine concentrations were lowest after complete inhibition (NE [nmol]: pre, 1.8±1.2; post, 2.4±1.8) and highest following peripheral inhibition (NE [nmol]: pre, 3.6±1.9; post, 6.6±4.4). Following fistula occlusion, rCBF (laser Doppler unit [LDU]) and rSO2 (%SO2) increases were highest after complete inhibition (pre: 204±14 LDU, 34± 3%SO2; post: 228±18 LDU, 39±3%SO2) and lowest after peripheral inhibition (pre: 221±18 LDU, 41±2%SO2; post: 226±14 LDU, 47±2%SO2). Thus, a complete inhibition down-regulates SNS activity and provokes a cortical hyperperfusion condition. With this, the hitherto unknown predominant role of the intrinsic component could be demonstrated for the first time in vivo. Keywords AVM . Animal model . CBF regulation . Norepinephrine . Sympathetic nervous system
Introduction Maintenance of an adequate cerebral blood flow (CBF) before and after excision of a cerebral arteriovenous malformation (AVM) could be proven in most of the cases [1–4]. The assumption that ne
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