title: Postnatal development of conduction velocity and fibre size in the rat tibial nerve.
abstract: The maximum conduction velocity (CV) and fibre diameters (D) were determined in the tibial nerve of developing rats. In 1-day-old rats CV of the fastest motor and sensory fibres (assessed separately) was 1.4 m/sec on the average and increased to 35 m/sec by postnatal day 30. The maximum conduction rate in adult rats ranged from 60 to 84 m/sec. Diameters of at least 100 nerve fibres in each age group were measured in electronmicrographs. The calibre of myelinating fibres in 1-day-old rats was 0.5-1.5 μm. By day 90 after birth the range of myelinated fibre size extended to 1.5-12.5 μm. The factor relating conduction rate and total fibre diameter of the largest fibres (i.e. the value of CV D ) was found to vary with age, increasing from 1.1 to 6.2 between postnatal days 1 and 90. These results indicate that functional and morphological properties of peripheral nerve fibres in the rat undergo considerable changes during postnatal ontogeny until they reach adult values.
authors.affiliation: Institute of Physiology, Czechoslovak Academy of Sciences, Vídeňská 1083, 142 20 Prague 4, Czechoslovakia.
authors.forename: R
authors.initials: R
authors.lastname: Vejsada
authors.forename: J
authors.initials: J
authors.lastname: Paleček
authors.forename: P
authors.initials: P
authors.lastname: Hník
authors.forename: T
authors.initials: T
authors.lastname: Soukup