The flow of mitochondria in chicken sciatic nerve

Abstract

Mitochondrial flow in chicken sciatic nerve has been followed using [⁵⁹Fe] as a marker for mitochondrial cytochromes.Radioactively labelled iron was injected into the ventral horn of the chicken spinal cord in the region of the cell bodies of the motor neurons, whose axons pass into the sciatic nerve. Protein‐bound [⁵⁹Fe] was found to move at a slow rate (1–4 mm/day) in the sciatic nerve. The total protein bound [⁵⁹Fe] in the nerve reached a maximum at 9 days and then gradually diminished.The percentage of label in the mitochondria (expressed both as total and protein bound radioactivity) as compared to the total homogenate of the spinal cord increased up to 14 days and then showed a gradual levelling off.Subcellular fractionation of both spinal cord and sciatic nerve revealed that the mitochondrial fraction obtained by discontinuous gradient centrifugation had the highest specific activity of the fractions isolated. The major portion of this label is present in cytochromes a and b, localized in the mitochondria.Colchicine which has been shown to inhibit both rapid and slow axonal protein flow, markedly reduced the amount of protein bound [⁵⁹Fe] in the sciatic nerve.