Nicotine-evoked disassembly of cortical actin filaments in adrenal chromaffin cells

Abstract

Using rhodamine-phalloidin staining it was found that actin filaments are concentrated in the cortex of resting chromaffin cells. Cortical actin filaments were disassembled 15 s after stimulation by nicotine and had reassembled 30 s later. Actin filament disassembly following nicotinic stimulation was also detected using the DNase I inhibition assay. Disassembly was independent of external calcium, insensitive to trifluoperazine and was not elicited by high K+, muscarinic agonists or phorbol ester. Disassembly of cortical actin filaments may allow access of secretory granules to exocytotic sites and act in conjunction with a rise in intracellular free calcium to bring about the full secretory response due to nicotinic agonists.