During the past 15 years, the presence of ion channels in synaptic vesicle and neurosecretory granule membrane preparations has been demonstrated repeatedly by different investigators. The physiological roles and molecular identity of these ion channels remained, however, enigmatic. The report of Yin et al. in this issue of The Journal of Physiology strengthens previous suggestions that at least one of these channels could be associated with, related to, or identical to, a major membrane protein of synaptic vesicles, synaptophysin.
