title: Bumetanide is not capable of terminating status epilepticus but enhances phenobarbital efficacy in different rat models.
abstract: In about 20-40% of patients, status epilepticus (SE) is refractory to standard treatment with benzodiazepines, necessitating second- and third-line treatments that are not always successful, resulting in increased mortality. Rat models of refractory SE are instrumental in studying the changes underlying refractoriness and to develop more effective treatments for this severe medical emergency. Failure of GABAergic inhibition is a likely cause of the development of benzodiazepine resistance during SE. In addition to changes in GABAA receptor expression, trafficking, and function, alterations in Cl(-) homeostasis with increased intraneuronal Cl(-) levels may be involved. Bumetanide, which reduces intraneuronal Cl(-) by inhibiting the Cl(-) intruding Na(+), K(+), Cl(-) cotransporter NKCC1, has been reported to interrupt SE induced by kainate in urethane-anesthetized rats, indicating that this diuretic drug may be an interesting candidate for treatment of refractory SE. In this study, we evaluated the effects of bumetanide in the kainate and lithium-pilocarpine models of SE as well as a model in which SE is induced by sustained electrical stimulation of the basolateral amygdala. Unexpectedly, bumetanide alone was ineffective to terminate SE in both conscious and anesthetized adult rats. However, it potentiated the anticonvulsant effect of low doses of phenobarbital, although this was only seen in part of the animals; higher doses of phenobarbital, particularly in combination with diazepam, were more effective to terminate SE than bumetanide/phenobarbital combinations. These data do not suggest that bumetanide, alone or in combination with phenobarbital, is a valuable option in the treatment of refractory SE in adult patients.
authors.affiliation: Department of Pharmacology, Toxicology, and Pharmacy, University of Veterinary Medicine Hannover, Germany; Center for Systems Neuroscience, Hannover, Germany.
authors.forename: Kathrin
authors.initials: K
authors.lastname: Töllner
authors.affiliation: Department of Pharmacology, Toxicology, and Pharmacy, University of Veterinary Medicine Hannover, Germany; Center for Systems Neuroscience, Hannover, Germany.
authors.forename: Claudia
authors.initials: C
authors.lastname: Brandt
authors.affiliation: Department of Medicinal Chemistry, University of Vienna, Austria.
authors.forename: Thomas
authors.initials: T
authors.lastname: Erker
authors.affiliation: Department of Pharmacology, Toxicology, and Pharmacy, University of Veterinary Medicine Hannover, Germany; Center for Systems Neuroscience, Hannover, Germany. Electronic address: wolfgang.loescher@tiho-hannover.de.
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Löscher
mesh_terms: D000818:Animals; D000927:Anticonvulsants / Q000494:pharmacology* / Q000627:therapeutic use; D066272:Basolateral Nuclear Complex / Q000187:drug effects; D002034:Bumetanide / Q000494:pharmacology*; D004195:Disease Models, Animal; D004357:Drug Synergism; D004558:Electric Stimulation; D007608:Kainic Acid / Q000494:pharmacology; D008094:Lithium / Q000494:pharmacology; D008297:Male; D010634:Phenobarbital / Q000494:pharmacology* / Q000627:therapeutic use; D010862:Pilocarpine / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley; D013226:Status Epilepticus / Q000139:chemically induced / Q000188:drug therapy*
chemical_list: D000927:Anticonvulsants; D010862:Pilocarpine; D002034:Bumetanide; D008094:Lithium; D007608:Kainic Acid; D010634:Phenobarbital
keywords: Amygdala; Cation cotransporters; GABA receptors; Kainate; Pilocarpine; Pilocarpine (PubChem CID: 5910)