Blood-brain barrier transport of butanol and water relative to N-isopropyl-p-iodoamphetamine as the internal reference
The literature regarding the blood--brain barrier (BBB) transport of butanol is conflicting as studies report both incomplete and complete extraction of butanol by the brain. In this work the BBB transport of both (/sup 14/C)butanol and (/sup 3/H)water was studied using the carotid injection technique in conscious and in ketamine- or pentobarbital-anesthetized rats employing N-isopropyl-p-(/sup 125/I)iodoamphetamine ((/sup 125/I)IMP) as the internal reference and as a fluid microsphere. The three isotopes (/sup 3/H, /sup 125/I, /sup 14/C) were conveniently counted simultaneously in a liquid scintillation spectrometer. IMP is essentially completely sequestered by the brain for at least 1 min in conscious rats and for 2 min in anesthetized animals. Butanol extraction by rat forebrain is not flow limited but ranges between 77 +/- 1 and 87 +/- 1% for the three conditions. The permeability-surface area product/cerebral blood flow ratio of butanol and water in rat forebrain remains relatively constant, despite a twofold increase in cerebral blood flow in conscious relative to pentobarbital-anesthetized rats. The absence of an inverse relationship between flow and butanol or water extraction is consistent with capillary recruitment being the principal mechanism underlying changes in cerebral blood flow in anesthesia. The diffusion restriction of BBB transport of butanol in some regions, but not in others, necessitates a careful regional analysis of BBB permeability to butanol prior to usage of this compound as a cerebral blood flow marker.
- Research Organization:
- Univ. of California, Los Angeles
- OSTI ID:
- 5019953
- Journal Information:
- J. Cereb. Blood Flow Metab.; (United States), Journal Name: J. Cereb. Blood Flow Metab.; (United States) Vol. 2; ISSN JCBMD
- Country of Publication:
- United States
- Language:
- English
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62 RADIOLOGY AND NUCLEAR MEDICINE
ALCOHOLS
AMPHETAMINES
ANALEPTICS
ANIMALS
AUTONOMIC NERVOUS SYSTEM AGENTS
BETA DECAY RADIOISOTOPES
BLOOD FLOW
BLOOD VESSELS
BLOOD-BRAIN BARRIER
BODY
BRAIN
BUTANOLS
CAPILLARIES
CARBON 14 COMPOUNDS
CARDIOVASCULAR SYSTEM
CENTRAL NERVOUS SYSTEM
CENTRAL NERVOUS SYSTEM AGENTS
CHALCOGENIDES
COUNTING TECHNIQUES
DAYS LIVING RADIOISOTOPES
DIFFUSION
DRUGS
ELECTRON CAPTURE RADIOISOTOPES
HYDROGEN COMPOUNDS
HYDROXY COMPOUNDS
INTERMEDIATE MASS NUCLEI
IODINE 125
IODINE ISOTOPES
ISOTOPES
LABELLED COMPOUNDS
MAMMALS
NERVOUS SYSTEM
NUCLEI
ODD-EVEN NUCLEI
ORGANIC COMPOUNDS
ORGANS
OXIDES
OXYGEN COMPOUNDS
PERMEABILITY
RADIOISOTOPES
RATS
RODENTS
SCINTILLATION COUNTING
SYMPATHOMIMETICS
TRITIUM COMPOUNDS
TRITIUM OXIDES
VERTEBRATES
WATER