The axonal transport of adrenergic and cholinergic axonal organelles in rat sciatic nerve has been studied using a cytofluorimetric scanning (CFS) technique. This technique gives quantitative data on material which accumulates in a nerve relative to a crush, as well as morphological and morphometrical information about the accumulated axons in the nerve. One important advantage is that several substances can be measured in the same nerve segment, thus reducing the number of animals needed. The substances must be made fluorescent, and in this study we have investigated noradrenaline (NA), using formaldehyde induced fluorescence, and dopamine beta-hydroxylase (DBH), tyrosine hydroxylase (TH), neuropeptide Y (NPY) and two cholinergic vesicle components (a transmembrane glycoprotein and synapsin I) using indirect immunofluorescence. The antisera used for labelling immunoreactive material (IR) were produced in rabbit or goat (DBH). In adrenergic axons NA, DBH-IR and TH-IR accumulated with time after crushing the nerve as described earlier with biochemical techniques. After reserpine, the amounts of amine granules transported distally in the sciatic nerve initially fell, but recovered during day 2 after reserpine. At day 4 the amount of NA and DBH-IR which was transported distally in the axons was supranormal, 160% and 140% of control, respectively, but the level of NPY-IR was not increased, even falling to subnormal at day 4, indicating different mechanisms for regulating the synthesis of DBH and NPY which are suggested to co-exist in axonal adrenergic large dense core vesicles. In cholinergic motor axons organelles, recognized by rabbit-anti-cholinergic synaptic vesicles-antiserum (RASVA) and by anti-synapsin I-antiserum, are transported distally at a rapid rate.(ABSTRACT TRUNCATED AT 250 WORDS)