The [Ca.sup.2+] required for exocytosis may enter the cnidocyte by way of the voltage-gated channels
that underlie the action potential in these cells (Anderson and McKay, 1987; Brinkmann et al., 1996; Oliver et al., 2008).
Neuropeptides are released from neurons through a process that -- like other secretory events -- is triggered primarily by the influx of calcium into the neuron through voltage-gated channels
. Although neuropeptides are stored in large dense core vesicles (LDCVs) that also contain large amounts of calcium, it has been unclear whether these locally based calcium supplies can also be used to modulate secretion.
Because the amino acid makeup of the bacterial potassium channel is similar to that of other voltage-gated channels
, especially in the paddle regions, it's likely that all such channels operate in the same way, predicts MacKinnon.