title: Effect of nimodipine on cerebral blood flow and metabolism in rats during hyperventilation.
abstract: Nimodipine shws promise in the prevention and treatment of brain ischemia. We examined the interaction of nimodipine pretreatment in a dose sufficient to prevent postischemic hypoperfusion and hyperventilation. We studied four groups of rats: normocarbia plus vehicle (Group 1, n = 5), hypocarbia plus vehicle (Group 2, n = 4), normocarbia plus nimodipine (Group 3, n = 7), and hypocarbia plus nimodipine (Group 4, n = 6). Groups 3 and 4 received 1 mg/kg i.p. nimodipine, and Groups 1 and 2 received an equivalent amount of vehicle. Ventilation was left unaltered in Groups 1 and 3 or increased to lower PaCO2 to 21-24 mm Hg in Groups 2 and 4. Determination of regional cerebral glucose utilization (rCGU) was carried out using the [3H]2-deoxyglucose method, and regional cerebral blood flow (rCBF) was determined by the indicator fractionation method using [14C]iodoantipyrine. The brain regions studied were the cerebral hemispheres, the diencephalon, the cerebellum, and the brainstem. Hyperventilation in Groups 2 and 4 from approximately 38 to 22 mm Hg reduced rCBF to 60% of normocarbic levels (p less than 0.05). The slope and intercept of this response were similar in vehicle- and nimodipine-pretreated rats. Nimodipine modestly decreased mean arterial blood pressure by 20% and increased plasma glucose concentration by 60% (p less than 0.05). Although nimodipine tended to increase rCBF and decrease regional cerebrovascular resistance (rCVR), this was significant only for hemispheric rCVR (p less than 0.05). There was a borderline effect for nimodipine to increase rCGU, especially during hypocarbia.(ABSTRACT TRUNCATED AT 250 WORDS)
authors.affiliation: Department of Anesthesiology, College of Physicians and Surgeons, Columbia University, New York, New York.
authors.forename: W L
authors.initials: WL
authors.lastname: Young
authors.forename: S
authors.initials: S
authors.lastname: Chien
mesh_terms: D000818:Animals; D001921:Brain / Q000378:metabolism*; D002560:Cerebrovascular Circulation / Q000187:drug effects*; D005947:Glucose / Q000378:metabolism; D006985:Hyperventilation / Q000378:metabolism / Q000503:physiopathology*; D008297:Male; D009553:Nimodipine / Q000494:pharmacology*; D051381:Rats; D011919:Rats, Inbred Strains; D012044:Regression Analysis; D014655:Vascular Resistance
chemical_list: D009553:Nimodipine; D005947:Glucose