title: Intracellular stimulation of mast cells with guanine nucleotides mimic antigenic stimulation.
abstract: Exocytosis was followed in single rat peritoneal mast cells, by measuring the cell membrane capacitance using circuit analysis and patch-clamp techniques. After antigenic stimulation or intracellular perfusion with guanine nucleotides, exocytosis followed a time course characterized by a lag period d, area expansion factor A, and a time constant tau. We suggest that A depends entirely on the cell's morphology, d reflects the properties of a GTP-binding regulatory protein that appears to rate limit the response and tau is due to an independent and yet unknown process. In contrast, cells stimulated by compound 48/80 can respond without a measurable delay and degranulate within 2 s, suggesting that this compound acts at a site after the GTP-binding regulatory protein.
mesh_terms: D000818:Animals; D005089:Exocytosis / Q000187:drug effects*; D019204:GTP-Binding Proteins / Q000378:metabolism; D006150:Guanine Nucleotides / Q000494:pharmacology*; D008407:Mast Cells / Q000187:drug effects* / Q000378:metabolism; D008564:Membrane Potentials; D051381:Rats; D003189:p-Methoxy-N-methylphenethylamine / Q000494:pharmacology
chemical_list: D006150:Guanine Nucleotides; D003189:p-Methoxy-N-methylphenethylamine; D019204:GTP-Binding Proteins