1.   As with Aplysia, a key player in this process appears to be calcium ions.

2.   The mineral calcite is made up of carbonate sheets and intervening planes of calcium ions.

3.   In the fluorite lattice, for example, there are two fluoride ions to every calcium ion.

4.   It has been suggsted that only soluble calcium ions precipitate fatty acids and bile acids, thus reducing their lytic activity.

5.   Bile salts are important buffers for calcium ion, which may act to reduce free calcium ions in the bile thereby reducing calcium lithogenicity.

6.   Calcium channel blockers slow the flow of calcium ions across certain cell membranes.

7.   Calcium channel blockers cause the relaxing of heart muscles and blood vessels by interfering with movement of calcium ions across cell membranes.

8.   One of the components is a membrane called the sarcoplasmic reticulum, which holds the calcium-uptake sites and little pouches of calcium ions.

9.   So by plugging the pores, diltiazem might prevent an abnormal influx of calcium ions that would kill those cells, Picaud said.