title: Effects of flumazenil during administration of midazolam on pial vessel diameter and regional cerebral blood flow in cats.
abstract: We implanted closed cranial windows in ten cats in order to observe the response of pial vessel diameter by microscopy using fluorescein isothiocyanate-labeled dextran and regional cerebral blood flow (rCBF) by laser Doppler flowmetry during administration of midazolam and reversal with flumazenil. Midazolam was given at 0.8 mg.kg-1 x min-1 for 10 min and maintained at 0.04 mg.kg-1 x min-1 for 50 min (total 10 mg.kg-1). The diameter of arterioles and venules and rCBF showed no significant change. During the last 10 min of midazolam administration, flumazenil, given at 0.1 mg.kg-1 x min-1 for 10 min (total 1 mg.kg-1), caused an increase of MAP and rCBF (P < 0.01) at 5 min after infusion and diameter of larger arterioles (> 50 microns) and venules (50-100 microns) were dilated (P < 0.05). These results indicate that midazolam does not affect the diameter of cerebral arterioles and venules; however, the reversal effects of flumazenil against midazolam are transient vasodilation of larger arterioles accompanied by an elevation of MAP, and an increase in CBF.
authors.affiliation: Department of Anaesthesiology, Nara Medical University, Japan.
authors.forename: H
authors.initials: H
authors.lastname: Kumano
authors.forename: T
authors.initials: T
authors.lastname: Shimomura
authors.forename: H
authors.initials: H
authors.lastname: Furuya
authors.forename: H
authors.initials: H
authors.lastname: Yomosa
authors.forename: T
authors.initials: T
authors.lastname: Okuda
authors.forename: T
authors.initials: T
authors.lastname: Sakaki
authors.forename: M
authors.initials: M
authors.lastname: Kuro
mesh_terms: D000818:Animals; D001160:Arterioles / Q000187:drug effects / Q000473:pathology; D001794:Blood Pressure / Q000187:drug effects; D002245:Carbon Dioxide / Q000097:blood; D002415:Cats; D002560:Cerebrovascular Circulation / Q000187:drug effects*; D003399:Craniotomy; D005442:Flumazenil / Q000008:administration & dosage / Q000494:pharmacology*; D006863:Hydrogen-Ion Concentration; D017078:Laser-Doppler Flowmetry; D008874:Midazolam / Q000008:administration & dosage / Q000037:antagonists & inhibitors / Q000494:pharmacology*; D010841:Pia Mater / Q000098:blood supply* / Q000187:drug effects; D014664:Vasodilation; D014699:Venules / Q000187:drug effects / Q000473:pathology
chemical_list: D002245:Carbon Dioxide; D005442:Flumazenil; D008874:Midazolam