Reversible Change of Extracellular pH at the Generation of Mechano-Induced Electrical Reaction in a Stem of Cucurbita pepo.

As was shown recently the generation of cooling-induced action potential accompanies the reversible change of extracellular pH.1 The pH changes are linked to the Ca(2+)-induced transient inhibition of the plasma membrane H(+)-ATPase. Generation of mechano-induced local bioelectrical reaction (LBER) also accompanies the reversible change of extracellular pH.

Subthreshold changes in excitable membranes of Cucurbits pepo L. stem cells during cooling-induced action-potential generation.

The nature of subthreshold changes in excitable plasma membranes has been investigated in stem parenchyma cells of Cucurbita pepo L. during action-potential generation induced by gradual cooling (from 23 to 10 ° C). The character of the subthreshold depolarization of excitable cells is shown to be mainly defined by a decrease in the activity of the plasma-membrane electrogenie pump (H(+)-ATPase).