title: Bumetanide enhances phenobarbital efficacy in a rat model of hypoxic neonatal seizures.
abstract: Neonatal seizures can be refractory to conventional anticonvulsants, and this may in part be due to a developmental increase in expression of the neuronal Na(+)-K(+)-2 Cl(-) cotransporter, NKCC1, and consequent paradoxical excitatory actions of GABAA receptors in the perinatal period. The most common cause of neonatal seizures is hypoxic encephalopathy, and here we show in an established model of neonatal hypoxia-induced seizures that the NKCC1 inhibitor, bumetanide, in combination with phenobarbital is significantly more effective than phenobarbital alone. A sensitive mass spectrometry assay revealed that bumetanide concentrations in serum and brain were dose-dependent, and the expression of NKCC1 protein transiently increased in cortex and hippocampus after hypoxic seizures. Importantly, the low doses of phenobarbital and bumetanide used in the study did not increase constitutive apoptosis, alone or in combination. Perforated patch clamp recordings from ex vivo hippocampal slices removed following seizures revealed that phenobarbital and bumetanide largely reversed seizure-induced changes in EGABA. Taken together, these data provide preclinical support for clinical trials of bumetanide in human neonates at risk for hypoxic encephalopathy and seizures.
authors.affiliation: Department of Neurology, Children's Hospital Boston, Boston, Massachusetts, United States of America.
authors.forename: Ryan T
authors.initials: RT
authors.lastname: Cleary
authors.forename: Hongyu
authors.initials: H
authors.lastname: Sun
authors.forename: Thanhthao
authors.initials: T
authors.lastname: Huynh
authors.forename: Simon M
authors.initials: SM
authors.lastname: Manning
authors.forename: Yijun
authors.initials: Y
authors.lastname: Li
authors.forename: Alexander
authors.initials: A
authors.lastname: Rotenberg
authors.forename: Delia M
authors.initials: DM
authors.lastname: Talos
authors.forename: Kristopher T
authors.initials: KT
authors.lastname: Kahle
authors.forename: Michele
authors.initials: M
authors.lastname: Jackson
authors.forename: Sanjay N
authors.initials: SN
authors.lastname: Rakhade
authors.forename: Gerard  T
authors.initials: G
authors.lastname: Berry
authors.forename: Gerard
authors.initials: G
authors.lastname: Berry
authors.forename: Frances E
authors.initials: FE
authors.lastname: Jensen
mesh_terms: D000818:Animals; D000831:Animals, Newborn; D000927:Anticonvulsants / Q000008:administration & dosage / Q000494:pharmacology; D001522:Behavior, Animal / Q000187:drug effects; D001921:Brain / Q000187:drug effects / Q000378:metabolism; D002034:Bumetanide / Q000008:administration & dosage* / Q000493:pharmacokinetics; D056547:CA1 Region, Hippocampal / Q000187:drug effects / Q000378:metabolism; D016923:Cell Death / Q000187:drug effects; D004357:Drug Synergism; D004359:Drug Therapy, Combination; D004569:Electroencephalography; D005071:Evoked Potentials / Q000187:drug effects; D000860:Hypoxia / Q000150:complications*; D008297:Male; D009474:Neurons / Q000187:drug effects / Q000378:metabolism; D010634:Phenobarbital / Q000008:administration & dosage* / Q000493:pharmacokinetics; D051381:Rats; D012640:Seizures / Q000188:drug therapy / Q000209:etiology* / Q000378:metabolism / Q000503:physiopathology; D049994:Sodium Potassium Chloride Symporter Inhibitors / Q000008:administration & dosage / Q000494:pharmacology; D064506:Solute Carrier Family 12, Member 2 / Q000378:metabolism; D027981:Symporters / Q000378:metabolism; D000096922:K Cl- Cotransporters
chemical_list: D000927:Anticonvulsants; D002034:Bumetanide; D010634:Phenobarbital; D049994:Sodium Potassium Chloride Symporter Inhibitors; D064506:Solute Carrier Family 12, Member 2; D027981:Symporters; D000096922:K Cl- Cotransporters
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