PH oscillations in cell suspensions of Dictyostelium discoideum: their relation to cyclic-amp signals.

Cells of Dictyostelium discoideum known to release cyclic AMP (cAMP) rhythmically in the form of pulses, change with the same period of about 8 min the pH of their medium. The pH is used here as an indicator to investigate the effect of externally added cAMP pulses on the oscillations. Both a temporary increase in amplitude and a permanent phase shift can be induced. The phase-response curve indicates that the period can be increased and decreased by rhythmic stimulation with cAMP pulses.