Activation-Induced Resetting of Cerebral Metabolism and Flow Is Abolished by β-Adrenergic Blockade With Propranolol
| Autor: | Peter Lund Madsen, Rasmus Linde, Ina K. Schmalbruch, Olaf B. Paulson |
|---|---|
| Rok vydání: | 2002 |
| Předmět: |
Blood Glucose
Male medicine.medical_specialty Glucose uptake Adrenergic beta-Antagonists Hemodynamics Propranolol Carbohydrate metabolism Rats Sprague-Dawley Oxygen Consumption Internal medicine medicine Animals Lactic Acid Cerebral Cortex Advanced and Specialized Nursing business.industry Metabolism Rats Blockade Kinetics medicine.anatomical_structure Endocrinology Cerebral blood flow Regional Blood Flow Cerebral cortex Cerebrovascular Circulation Neurology (clinical) Cardiology and Cardiovascular Medicine business medicine.drug |
| Zdroj: | Stroke. 33:251-255 |
| ISSN: | 1524-4628 0039-2499 |
| DOI: | 10.1161/hs0102.101233 |
| Popis: | Background and Purpose — It has previously been shown that activation will increase cerebral blood flow (CBF) and cerebral glucose uptake (CMR glc ) in excess of cerebral oxygen uptake (CMRO 2 ). Our purpose was to investigate the influence of β-adrenergic blockade with propranolol on the activation-induced uncoupling of cerebral glucose and oxygen metabolism. Methods — Using awake rats, we determined the cerebral arteriovenous differences of oxygen [(a−v) O2 ], glucose [(a−v) glc ], and lactate [(a−v) lac ] both under baseline conditions and during activation. The molar ratio between CMRO 2 and CMR glc , the oxygen-glucose index (OGI), was calculated. Results — Without β-adrenergic blockade, activation decreased the (a−v) O2 but not the (a−v) glc , reducing the OGI from 6.1 during baseline conditions to 4.0 under activation ( P O2 decreased, indicating that the ratio CBF/CMRO 2 had increased. Under baseline conditions, a slight flux of lactate from the brain was observed. Activation increased the arterial lactate concentration, and during this condition, the lactate flux from the brain was reversed into a slight lactate uptake. Propranolol administration did not change the behavior of the animals during activation. After administration of propranolol, baseline values were unaffected, but β-adrenergic blockade totally abolished the activation-induced uncoupling of (a−v) O2 from (a−v) glc , because both remained constant with an unchanged OGI. The unchanged (a−v) O2 indicates that CBF remained unchanged compared with CMRO 2 . Conclusions — β-Adrenergic blockade by propranolol abolishes the activation-induced uncoupling of cerebral oxygen to glucose metabolism and the changes in (a−v) O2 . This may be of most significance to studies of cerebral activation by the blood oxygen level–dependent fMRI method. |
| Databáze: | OpenAIRE |
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