It was designated F1, then B-50, then GAP43, pp46, and finally neuromodulin, each name reflecting a different function of the same molecule. F1 was localized to synapses, and was increased in its phosphorylation one day after learning.
The same molecule is referred to by multiple names: F1, B-50, GAP43, pp46, and neuromodulin, reflecting its diverse functions.