The uptake and retrograde transport of horseradish peroxidase--polylysine conjugate by ligated postganglionic sympathetic nerves in vitro.

The uptake and retrograde transport of horseradish peroxidase (HRP) and horseradish peroxidase-poly-L-lysine conjugate (HRP-PL) were compared using a system comprising the guinea-pig inferior mesenteric ganglion (IMG) and ligated hypogastric hypogastric nerves maintained in vitro in a twin chamber apparatus. 0.5 mg of HRP-PL applied to the ligated nerves produced stronger retrograde labelling of neurons within the IMG than did 10 mg of HRP. This may have been due to the greater uptake of HRP-PL in a vesicular form by the axons immediately proximal to the ligation. The possible roles of large rounded vesicles and elongated cisternae in retrograde axoplasmic transport are discussed.