title: Age-dependent morphine partitioning between plasma and cerebrospinal fluid in monkeys.
abstract: Steady-state partitioning of morphine between blood and cerebrospinal fluid (CSF) was evaluated in pigtailed monkeys at three ages: 2-3 days, 1 month and 1 year. Protein binding of morphine to serum proteins was assessed by ultrafiltration. Newborns showed a higher CSF to plasma ratio than the 1-month- or 1-year-old monkeys (0.506 vs. 0.369 or 0.374, respectively). Protein binding of morphine was 11% in newborns, and 17% at 1 year of age, not explaining the increased morphine penetration into CSF in newborns. Increased CSF morphine is a transient finding in infant macaques, which appears to reach young adult values by 1 month of age.
authors.affiliation: Department of Anesthesiology, School of Medicine, University of Washington, Seattle.
authors.forename: A M
authors.initials: AM
authors.lastname: Lynn
authors.forename: T I
authors.initials: TI
authors.lastname: McRorie
authors.forename: J T
authors.initials: JT
authors.lastname: Slattery
authors.forename: D F
authors.initials: DF
authors.lastname: Calkins
authors.forename: K E
authors.initials: KE
authors.lastname: Opheim
mesh_terms: D000375:Aging / Q000097:blood / Q000134:cerebrospinal fluid / Q000378:metabolism*; D000818:Animals; D000831:Animals, Newborn; D001812:Blood-Brain Barrier / Q000502:physiology; D002490:Central Nervous System / Q000378:metabolism*; D006221:Halothane / Q000494:pharmacology; D007262:Infusions, Intravenous; D008254:Macaca nemestrina; D009020:Morphine / Q000097:blood / Q000134:cerebrospinal fluid / Q000493:pharmacokinetics*
chemical_list: D009020:Morphine; D006221:Halothane