Tetraethylammonium selectively stimulates secretion from noradrenergic bovine chromaffin cells.
1. The effects of tetraethylammonium chloride (TEA) on catecholamine secretion from primary cultures of noradrenaline-rich (noradrenergic) and adrenaline-rich (adrenergic) bovine chromaffin cells were studied. TEA stimulated catecholamine secretion from both cell types but was a much more effective secretory stimulus for noradrenergic cells. 2. TEA-induced catecholamine secretion was dependent on extracellular Ca2+, was partially inhibited by nifedipine and by tetrodotoxin, and was potentiated by ouabain. Other K+ channel blocking agents including 4-aminopyridine, glibenclamide, and tolbutamide did not stimulate catecholamine secretion. 3. TEA had no effect on Ca(2+)-induced secretion from digitonin-permeabilized chromaffin cells. 4. TEA presumably evokes secretion by inhibiting K+ channels, depolarizing chromaffin cells, and activating voltage-gated Ca2+ channels in the cells. Noradrenergic cells appear to be more sensitive to K+ channel inhibition than are adrenergic cells. 5. The secretory response of the chromaffin cells to TEA increased with time in culture. 6. In addition to being a more effective secretagogue in noradrenergic cells, TEA was also more effective in stimulating catecholamine synthesis in these cells.
Cahill
A L
AL
Department of Pediatrics, University of Chicago, IL 60637.
Perlman
R L
RL
D015761:4-Aminopyridine / Q000494:pharmacology; D000818:Animals; D002118:Calcium / Q000378:metabolism; D002395:Catecholamines / Q000378:metabolism*; D002417:Cattle; D002478:Cells, Cultured; D002838:Chromaffin System / Q000166:cytology* / Q000187:drug effects; D004347:Drug Interactions; D004357:Drug Synergism; D004837:Epinephrine / Q000502:physiology; D005905:Glyburide / Q000494:pharmacology; D009543:Nifedipine / Q000494:pharmacology; D009638:Norepinephrine / Q000502:physiology; D010042:Ouabain / Q000494:pharmacology; D015240:Phorbol 12,13-Dibutyrate / Q000494:pharmacology; D026902:Potassium Channel Blockers; D019789:Tetraethylammonium; D013757:Tetraethylammonium Compounds / Q000494:pharmacology*; D013779:Tetrodotoxin / Q000494:pharmacology; D014044:Tolbutamide / Q000494:pharmacology
D002395:Catecholamines; D026902:Potassium Channel Blockers; D013757:Tetraethylammonium Compounds; D015240:Phorbol 12,13-Dibutyrate; D013779:Tetrodotoxin; D010042:Ouabain; D019789:Tetraethylammonium; D014044:Tolbutamide; D015761:4-Aminopyridine; D009543:Nifedipine; D005905:Glyburide; D002118:Calcium; D009638:Norepinephrine; D004837:Epinephrine