flunarizine and Dystonia

The Na leak-current channel (NALCN) regulates the resting membrane potential in excitable cells, thus determining the likelihood of depolarization in response to incoming signals. Gain-of-function (gf) mutations in this channel are associated with severe dystonic movement disorders in man. Currently, there are no known pharmacological antagonists or selective modulators of this important channel. A gain-of-function mutation in NALCN of C. elegans [known as unc-77(e625)] causes uncoordinated, hyperactive locomotion. We hypothesized that this hyperactive phenotype can be rescued with pharmacological modulators. Here, we summarize the results of targeted drug screening aimed at identification of drugs that corrected locomotion deficits in unc-77(e625) animals. To assay hyperactive locomotion, animals were acutely removed from food and characteristic foraging movements were quantified. Drug screening revealed that 2-aminoethoxydiphenyl borate (2-ABP), nifedipine, nimodipine, flunarizine and ethoxzolamide significantly decreased abnormal movements in unc-77(e625) animals. 2-APB also corrected egg release and coiling deficits in this strain. In addition, serotonin and dopamine both reduced hyperactive locomotion, consistent with regulatory interactions between these systems and the NALCN. 2-APB induced movement phenotypes in wild-type animals that faithfully mimicked those observed in NALCN knockout strains, which suggested that this drug may directly block the channel. Moreover, 2-APB and flunarizine showed significant structural similarities suggestive of overlap in their mode of action. Together, these studies have revealed new insights into regulation of NALCN function and led to the discovery of a potential pharmacological antagonist of the NALCN.

Topics: Animals; Boron Compounds; Caenorhabditis elegans; Caenorhabditis elegans Proteins; Dystonia; Ethoxzolamide; Flunarizine; Gain of Function Mutation; Gene Knockout Techniques; Ion Channels; Motor Disorders; Nifedipine; Nimodipine; Phenotype; Sodium Channels

We herein report the findings of a 2-year-6-month-old boy, who had been experiencing monocular pendular nystagmus, strabismus, and episodic eye deviation nystagmus, intractable dystonia and apneic attack which all began when he was 2 days of age. He underwent a complete blood count test, blood chemistry test, analysis of amino acids in the blood and urine, analysis of pyruvate/lactate in blood and cerebrospinal fluid, head computed tomography and magnetic resonance imaging and no abnormal results were identified. His attacks were resistant to multiple antiepileptic and dopaminergic drugs. He showed transient left and/or right hemiplegia after nystagmus, dystonia and/or apneic attacks at 8-months of age with retardation in intelligence. We diagnosed him to have alternating hemiplegia of childhood (AHC). We were unsure how to deal with his attacks after he was discharged from the hospital, however, resuscitation with the ambu bag by his mother at home and the intravenous infusion of diazepam or thiamylal at the hospital together was proven to be an effective method for treating his severe apneic attacks. The effect of diazepam and amantadine on these attacks was transient, however, the administration of flunarizine with amantadine resulted in an improvement in his attacks. We therefore consider the administration of flunarizine to be essential for the effective treatment of AHC in this case.

Topics: Amantadine; Anticonvulsants; Apnea; Child, Preschool; Dystonia; Flunarizine; Hemiplegia; Humans; Male; Nystagmus, Pathologic; Respiration, Artificial

Alternating hemiplegia of childhood is a rare disorder characterized by recurrent attacks of hemiplegia affecting either side of the body, oculomotor and autonomic disturbances, movement disorders, and progressive cognitive impairment. We report on one family with autosomal dominant alternating hemiplegia. The disorder was first recognized in a 9-year-old child, the third son of the family, who presented with learning disability, tonic-clonic seizures, dystonic attacks, and episodes of alternating hemiplegia starting at the age of 2 1/2 years. His mother and three brothers had similar symptoms. The maternal uncle, who has learning disability, had experienced multiple dystonic attacks. Tests performed on the family, including computerized tomography, magnetic resonance imaging, and magnetic resonance angiography of the brain as well as metabolic evaluation, were normal. Cytogenetic analysis was normal and mitochondrial DNA analysis revealed no deletions or mutations in the four affected family members and the grandmother. An autosomal dominant mode of inheritance is suggested by the fact that both sexes are affected in two generations.

Topics: Adult; Anticonvulsants; Child; Dystonia; Family Health; Female; Flunarizine; Genes, Dominant; Hemiplegia; Humans; Male; Neurologic Examination; Pedigree; Seizures; Syndrome

We report 2 children with early onset of hypotonia and frequent episodes of paroxysmal dystonia. The episodes were abolished even by brief naps. One of the children developed alternating hemiplegia in the second decade. These children seem to have a variant of the now well-recognized syndrome of alternating hemiplegia of childhood. In that disorder, episodes of alternating hemiplegia develop before the age of 18 months. This syndrome must be considered in the differential diagnosis of paroxysmal dystonia in childhood.

Topics: Adolescent; Athetosis; Brain; Child, Preschool; Chorea; Dystonia; Electroencephalography; Female; Flunarizine; Functional Laterality; Hemiplegia; Humans; Intellectual Disability; Muscle Hypotonia

Over the last few years, cases of movement disorders induced by flunarizine and cinnarizine have been increasingly reported. We describe a series of 101 patients, whose ages ranged from 37 to 84 years (mean 69.1), developing abnormal movements frequently associated with depression, secondary to treatment with either or both drugs. Symptoms closely resembled those induced by neuroleptic drugs and remitted on drug discontinuance in all but five cases after 5-22 months' follow-up. Whether or not such undesirable side effects are attributable to calcium antagonism and/or dopamine receptor blockade, long-term treatment with flunarizine or cinnarizine should be discouraged, particularly in the elderly.

Topics: Adult; Aged; Aged, 80 and over; Basal Ganglia Diseases; Cinnarizine; Depression; Dyskinesia, Drug-Induced; Dystonia; Female; Flunarizine; Humans; Male; Middle Aged; Parkinson Disease, Secondary; Tremor