Capacitance measurements reveal stepwise fusion events in degranulating mast cells.

摘要: Mast cells undergo an extensive and violent morphological transformation on stimulation. Here we describe the dynamics of fusion secretory granules in individual mast during exocytosis. The cell membrane capacitance (proportional to surface area) was measured using whole-cell patch-pipette technique, which intracellular space is dialysed with solutions used fill patch pipette. Our results show that degranulation occurs spontaneously reproducibly if GTP analogue, GTP-gamma-S, Mg-ATP are present pipette filling solution. Contrary previous reports, these conditions Ca2+ (and/or buffers) not required for degranulation. Although electrogenic entry detected before or conductance remained low, capacitance, by implication area degranulating cells, increased sigmoidally stepwise. We conclude stepwise increases due plasma membrane, guanine nucleotide regulatory proteins involved control this process.