Altered presynaptic ultrastructure in excitatory hippocampal synapses of mice lacking dystrophins Dp427 or Dp71

► Invertebrate models suggest dystrophins retrogradely regulate transmitter release. ► We examined brain excitatory presynaptic ultrastructure in mice lacking Dp427 or Dp71. ► Dp427 loss increases number of docked vesicles and reduces undocked vesicle size. ► Dp71 loss alters vesicles pool organization, vesicle size and synaptic cleft width. ► Presynaptic alterations may contribute to cognitive deficits in muscular dystrophy.