The remembrance of the things past: Conserved signalling pathways link protozoa to mammalian nervous system

•This review analyses evolutionary links between protozoa and neuronal and neurosecretory cells.•Several fundamental mechanisms are conserved, albeit with different subcellular channel localisation, from protozoans to man.•Most impressive example of evolutionary conservation is the sub-second dynamics of exocytosis-endocytosis coupling in both systems.