Table 3.

Cellular and molecular similarities between human neuron and sperm.

neuron	sperm
activate other cells: neurons or somatic effectors	activate other cells: oocyte
exocytosis of neurotransmitters in the synaptic space (essential for neuron function)	acrosomal exocytosis at the oocyte surface (essential for sperm function)
synaptic vesicles	acrosome
high concentrations of PUFAs
presence of ‘neuronal’ receptors
excitable cells
presence of Ca2+ channels
Ca2+ signalling involved in regulation of key functions
common signalling pathways