Figure 7. Effects of reduced [Ca²⁺]_o and nifedipine on slow waves and contractions.

A and B, simultaneous recordings of slow waves and phasic contractions in corpus and antrum in response to reduction in [Ca²⁺]_o from 2.5 mm to nominally free [Ca²⁺]_o. Note nearly total inhibition of contractions and slight reduction in amplitude and durations of slow waves. Tone is also reduced in both muscles with the reduction in amplitude. Break in A represents 20 min gap in the recording during a continous impalement. C, response of an antral muscle to nifedipine (1 μm). Note reduction, but not block, of contractions with this compound and little or no effect on slow waves. Break represents 10 min gap in recording during a continuous impalement.