title: Activity-dependent K+ accumulation in the developing rat optic nerve.
abstract: Potassium-sensitive microelectrodes were used to study activity-dependent changes of extracellular potassium ion concentration ([K+]o) in rat optic nerves of different postnatal ages (1 day to adulthood). The maximum level to which [K+]o rose with optimal frequencies of stimulation depended on age: mean maximum evoked [K+]o was 17.2 microM in 1- to 3-day-old optic nerves and 9.8 microM in adult nerves. The ceiling [K+]o seen in immature optic nerves, which is uniquely large for a mammalian central nervous system structure, may result from a relatively enhanced rate of evoked K+ release.
mesh_terms: D000375:Aging; D000818:Animals; D000831:Animals, Newborn; D004558:Electric Stimulation; D005071:Evoked Potentials; D009474:Neurons / Q000502:physiology; D009900:Optic Nerve / Q000254:growth & development* / Q000502:physiology; D011188:Potassium / Q000378:metabolism*; D051381:Rats
chemical_list: D011188:Potassium