potassium-bromide and Disease-Models--Animal

A seminal study recently demonstrated that bromide (Br-) has a critical function in the assembly of type IV collagen in basement membrane (BM), and suggested that Br- supplementation has therapeutic potential for BM diseases. Because salts of bromide (KBr and NaBr) have been used as antiepileptic drugs for several decades, repositioning of Br- for BM diseases is probable. However, the effects of Br- on glomerular basement membrane (GBM) disease such as Alport syndrome (AS) and its impact on the kidney are still unknown. In this study, we administered daily for 16 weeks 75 mg/kg or 250 mg/kg (within clinical dosage) NaBr or NaCl (control) via drinking water to 6-week-old AS mice (mouse model of X-linked AS). Treatment with 75 mg/kg NaBr had no effect on AS progression. Surprisingly, compared with 250 mg/kg NaCl, 250 mg/kg NaBr exacerbated the progressive proteinuria and increased the serum creatinine and blood urea nitrogen in AS mice. Histological analysis revealed that glomerular injury, renal inflammation and fibrosis were exacerbated in mice treated with 250 mg/kg NaBr compared with NaCl. The expressions of renal injury markers (Lcn2, Lysozyme), matrix metalloproteinase (Mmp-12), pro-inflammatory cytokines (Il-6, Il-8, Tnf-α, Il-1β) and pro-fibrotic genes (Tgf-β, Col1a1, α-Sma) were also exacerbated by 250 mg/kg NaBr treatment. Notably, the exacerbating effects of Br- were not observed in wild-type mice. These findings suggest that Br- supplementation needs to be carefully evaluated for real positive health benefits and for the absence of adverse side effects especially in GBM diseases such as AS.

Topics: Animals; Blood Urea Nitrogen; Bromides; Creatinine; Disease Models, Animal; Glomerular Basement Membrane; Kidney; Kidney Diseases; Liver Cirrhosis; Male; Mice; Mice, Inbred C57BL; Nephritis; Nephritis, Hereditary; Nitrogen; Potassium Compounds; Proteinuria; Sodium Compounds

Mutations in the SCN1A gene, which encodes the α1 subunit of voltage-gated sodium channels, cause generalized epilepsy with febrile seizures plus (GEFS+) and severe myoclonic epilepsy of infancy (SMEI). N1417H-Scn1a mutant rats are considered to be an animal model of human FS+ or GEFS+. To assess the pharmacologic validity of this model, we compared the efficacies of eight different antiepileptic drugs (AEDs) for the treatment of hyperthermia-induced seizures using N1417H-Scn1a mutant rats.. AEDs used in this study included valproate, carbamazepine (CBZ), phenobarbital, gabapentin, acetazolamide, diazepam (DZP), topiramate, and potassium bromide (KBr). The effects of these AEDs were evaluated using the hot water model, which is a model of experimental FS. Five-week-old rats were pretreated with each AED and immersed in water at 45°C to induce hyperthermia-induced seizures. The seizure manifestations and video-electroencephalographic recordings were evaluated. Furthermore, the effects of each AED on motor coordination and balance were assessed using the balance-beam test.. KBr significantly reduced seizure durations, and its anticonvulsant effects were comparable to those of DZP. On the other hand, CBZ decreased the seizure threshold. In addition, DZP and not KBr showed significant impairment in motor coordination and balance.. DZP and KBr showed potent inhibitory effects against hyperthermia-induced seizures in the Scn1a mutant rats, whereas CBZ exhibited adverse effects. These responses to hyperthermia-induced seizures were similar to those in patients with GEFS+ and SMEI. N1417H-Scn1a mutant rats may, therefore, be useful for testing the efficacy of new AEDs against FS in GEFS+ and SMEI patients.

Topics: Animals; Anticonvulsants; Bromides; Disease Models, Animal; Electroencephalography; Epilepsies, Myoclonic; Epilepsy, Generalized; Fever; Humans; Male; Mutation; NAV1.1 Voltage-Gated Sodium Channel; Nerve Tissue Proteins; Potassium Compounds; Rats; Rats, Mutant Strains; Seizures, Febrile; Sodium Channels; Video Recording

Human seizure disorders are a major health concern due to the large number of affected individuals, the potentially devastating consequences of untreated seizure occurrences, and the lack of an effective treatment for all patients. Although anticonvulsants have proven very helpful in treating seizures and remain the best option available for treatment, not all afflicted individuals respond to medication and many only do so in unique drug combinations or at the cost of adverse side-effects. Therefore, new and more effective anticonvulsants are continually sought after to combat this illness. In this study, we present results which offer the possibility of using Drosophila bang-sensitive (BS) mutants as a tool to screen anticonvulsants. By feeding the BS mutants a known anticonvulsant, potassium bromide, we have demonstrated that the drug dramatically reduces the seizures of bang senseless, the most severe of the BS mutants. This methodology suggests that the Drosophila system can potentially be a powerful instrument for assaying and testing new compounds with anticonvulsant properties.

Topics: Administration, Oral; Animals; Anticonvulsants; Bromides; Disease Models, Animal; Drosophila; Drosophila Proteins; Drug Evaluation, Preclinical; Electrophysiology; Mutation; Paralysis; Potassium Compounds; Refractory Period, Electrophysiological; Seizures; Species Specificity

Ataxia, sedation, amnesia, ethanol and barbiturate potentiation, loss of efficacy (tolerance), development of dependence, and the potential for drug abuse limit the clinical use of benzodiazepines (BZDs) for long-term treatment of epilepsy or anxiety. BZD ligands that are in current use act as full allosteric modulators of gamma-aminobutyric acid (GABA)-gated chloride channels and, on long-term administration, trigger a functional uncoupling between the GABAA and BZD recognition sites. Partial allosteric modulators, which have a low intrinsic activity at the BZD recognition site of the GABAA receptor, might eventually overcome the limitations of full agonists such as diazepam (DZP).. In the present study, the new low-affinity partial BZD-receptor agonist ELB 138 [former name AWD 131-138; 1-(4-chlorophenyl)-4-morpholino-imidazolin-2-one] was evaluated in a dog seizure model and in epileptic dogs with spontaneously recurrent seizures.. ELB 138 was shown to increase potently the pentylenetetrazole (PTZ) seizure threshold in dogs. Prolonged oral administration with twice-daily dosing of ELB 138 with either 5 or 40 mg/kg over a 5-week period was not associated with loss of anticonvulsant efficacy in the PTZ dog model. To study whether physical dependence developed during long-term treatment, the BZD antagonist flumazenil was injected after 5 weeks of treatment with ELB 138. Compared with prolonged treatment with DZP, only relatively mild abstinence symptoms were precipitated in dogs treated with ELB 138, particularly at the lower dosage (5 mg/kg, b.i.d.). In a prospective trial in dogs with newly diagnosed epilepsy, ELB 138 markedly reduced seizure frequency and severity without significant difference to standard treatments (phenobarbital or primidone) but was much better tolerated than the standard drugs. In dogs with chronic epilepsy, most dogs exhibited a reduction in seizure frequency and severity during add-on treatment with ELB 138.. The data demonstrate that the partial BZD receptor agonist ELB 138 exerts significant anticonvulsant efficacy without tolerance in a dog seizure model as well as in epileptic dogs with spontaneously recurrent seizures. These data thus substantiate that partial agonism at the BZD site of GABAA receptors offers advantages versus full agonism and constitutes a valuable approach for treatment of seizures.

Topics: Animals; Anticonvulsants; Bromides; Chronic Disease; Disease Models, Animal; Dog Diseases; Dogs; Drug Therapy, Combination; Epilepsy; Flumazenil; GABA Agonists; GABA-A Receptor Agonists; Imidazoles; Pentylenetetrazole; Phenobarbital; Potassium Compounds; Primidone; Receptors, GABA-A; Seizures; Substance Withdrawal Syndrome; Treatment Outcome