Figure 5. The effect of ryanodine.

The effect of 30 mm ryanodine on Ca²⁺ oscillations is shown. Within 80 s of drug addition, oscillations had ceased completely, and this was accompanied by an increase in basal Ca²⁺ concentration within the cell. The effects of ryanodine were irreversible even on prolonged washout. In 12 such experiments this concentration of ryanodine invariably abolished spontaneous oscillations. The effect on basal Ca²⁺ level was also a consistent one with normalized level increasing from 1.0 ± 0.007 before drug addition to 1.30 ± 0.065 in the presence of 30 mm ryanodine.