Real-time measurements of acetylcholine-induced release of ATP from bovine medullary chromaffin cells.
The luminescent oxidation of luciferin has been used to monitor acetylcholine-induced ATP release from cultured bovine chromaffin cells. Acetylcholine (1-100 microM) evoked ATP release of up to 30% of the total cellular ATP. This secretion required external free calcium and could also be elicited by K+-induced membrane depolarization. The size of the cytosolic ATP compartment was estimated as 5% of the ATP in the cell by solubilising the cell membrane using digitonin (20 microM) or by application to the cells of brief pulses (2 microseconds) of high electric field (2000 V/cm). Blockers of the voltage-gated Ca2+ channel effectively blocked K+-induced ATP release, while the acetylcholine antagonists d-tubocurarine and beta-bungarotoxin inhibited the acetylcholine-induced release of ATP. These data support the concept that ATP is released together with the catecholamines by exocytosis of chromaffin granule contents.
D000109:Acetylcholine / Q000494:pharmacology*; D000255:Adenosine Triphosphate / Q000378:metabolism*; D000313:Adrenal Medulla / Q000378:metabolism*; D000818:Animals; D002118:Calcium / Q000502:physiology; D002417:Cattle; D002463:Cell Membrane Permeability; D002837:Chromaffin Granules / Q000378:metabolism*; D002838:Chromaffin System / Q000378:metabolism*; D003600:Cytosol / Q000378:metabolism; D004072:Digitonin; D049454:Firefly Luciferin; D008156:Luciferases; D011978:Receptors, Nicotinic / Q000187:drug effects
D011978:Receptors, Nicotinic; D049454:Firefly Luciferin; D000255:Adenosine Triphosphate; D008156:Luciferases; D004072:Digitonin; D000109:Acetylcholine; D002118:Calcium