Figure 8. Effects of caffeine, caffeine plus ryanodine and CPA on evoked slow waves.

Aa, in the presence of 1 μm nifedipine, slow waves were evoked by trains of impulses (supramaximal currents, 100 μs, 20 Hz, 0.25 s). Ab, caffeine (3 mM) abolished slow waves leaving residual responses which appeared to be summed EJPs. Ba, in the presence of nifedipine (1 μm) slow waves were evoked by similar trains of impulses. Bb, co-application of caffeine (3 mM) and ryanodine (10 μm) irreversibly abolished evoked slow waves and left summed EJPs after 1 h washout. Cb, CPA (10 μm) abolished evoked slow waves, again leaving summed EJPs. All traces were recorded in the same preparation and each trace was an average of 3-5 recordings. The scale bars on the right refer to all traces. RMP, resting membrane potential.