title: Age-dependent effects on sensory axonal excitability in normal mice.
abstract: Serial recordings were performed to measure sensory excitability in peripheral nerves and elucidate age-dependent changes in neuronal ion currents in the peripheral sensory nervous system. The threshold tracking technique was used to measure multiple excitability indices in the tail sensory nerves of five normal male mice at four time points (6, 10, 14, and 19 weeks of age). A separate group of four mice was also measured at 43 weeks and at 60 weeks of age. Maturation was accompanied by an increase in early hyperpolarization and superexcitability at 10 weeks. At 60 weeks, the hyperpolarizing electrotonus shifted downward, while superexcitability became greater and subexcitability (double stimuli) decreased. Computer modeling showed that the most notable age-related interval changes in excitability parameters were Barrett-Barrett, H, and slow K(+) conductances. Understanding age-related changes in the excitability of sensory axons may provide a platform for understanding age-dependent sensory symptoms and developing age-specific channel-targeting therapies.
authors.affiliation: Department of Neurology, Tokushima University, Tokushima, Japan.
authors.forename: Chimeglkham
authors.initials: C
authors.lastname: Banzrai
authors.affiliation: Department of Neurology, Tokushima University, Tokushima, Japan. Electronic address: hnodera@tokushima-u.ac.jp.
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Nodera
authors.affiliation: Department of Neurology, Tokushima University, Tokushima, Japan.
authors.forename: Saki
authors.initials: S
authors.lastname: Higashi
authors.affiliation: Department of Neurology, Tokushima University, Tokushima, Japan.
authors.forename: Ryo
authors.initials: R
authors.lastname: Okada
authors.affiliation: Department of Neurology, Tokushima University, Tokushima, Japan.
authors.forename: Yusuke
authors.initials: Y
authors.lastname: Osaki
authors.affiliation: Department of Neurology, Tokushima University, Tokushima, Japan.
authors.forename: Atsuko
authors.initials: A
authors.lastname: Mori
authors.affiliation: Department of Neurology, Tokushima University, Tokushima, Japan.
authors.forename: Ryuji
authors.initials: R
authors.lastname: Kaji
mesh_terms: D000200:Action Potentials; D000375:Aging / Q000502:physiology*; D000818:Animals; D001369:Axons / Q000502:physiology*; D003198:Computer Simulation; D004558:Electric Stimulation; D007473:Ion Channels / Q000502:physiology; D008297:Male; D008813:Mice, Inbred ICR; D008959:Models, Neurological; D009046:Motor Neurons / Q000502:physiology; D010525:Peripheral Nerves / Q000502:physiology; D011984:Sensory Receptor Cells / Q000502:physiology*; D012684:Sensory Thresholds; D013623:Tail / Q000294:innervation
chemical_list: D007473:Ion Channels
keywords: Age-related change; Axonal excitability; Ion conductance; Sensory nerve