title: Effects of botulinum toxin on strength-duration properties.
abstract: Axonal excitability studies have been used in several diseases to investigate the underlying pathophysiology. The threshold tracking technique was developed to measure noninvasively several indices of axonal excitability, such as strength-duration properties. This study investigated the possible effects of botulinum toxin on strength-duration time constant (SDTC) in patients with the symptoms and signs of botulism. The clinical and electrophysiological findings of 13 patients who were admitted to the authors' clinic with botulism signs and symptoms were evaluated in a 5-day period after exposure to the toxin prospectively. After routine diagnostic electroneuromyographic examinations and electromyogram with repetitive nerve stimulation at 20-50 Hz, SDTC was studied. The results were compared with 13 age- and sex-matched healthy volunteers. The SDTCs were 381 +/- 60 micros and 471 +/- 84 micros in patients and controls, respectively. There was a statistical difference between the two groups (p = .003, Mann Whitney U test). These findings suggest a possible effect of botulinum toxin, known to be effective at neuromuscular junction, on Na(+)/K(+) pump activity, and Na(+) or K(+) conductance.
authors.affiliation: Department of Neurology, Cukurova University Medical School, Adana, Turkey.
authors.forename: Deniz
authors.initials: D
authors.lastname: Yerdelen
authors.forename: Filiz
authors.initials: F
authors.lastname: Koc
authors.forename: Yakup
authors.initials: Y
authors.lastname: Sarica
mesh_terms: D000328:Adult; D001369:Axons / Q000187:drug effects / Q000502:physiology*; D001905:Botulinum Toxins / Q000009:adverse effects* / Q000506:poisoning; D001906:Botulism / Q000175:diagnosis / Q000503:physiopathology*; D004576:Electromyography; D006801:Humans; D008297:Male; D008875:Middle Aged; D018482:Muscle, Skeletal / Q000294:innervation / Q000502:physiology; D009431:Neural Conduction / Q000187:drug effects / Q000502:physiology*; D011042:Poisons / Q000009:adverse effects*
chemical_list: D011042:Poisons; D001905:Botulinum Toxins