Molecular Pharmacology, Vol 5, 294-299, Copyright © 1969 by the American Society for Pharmacology and Experimental Therapeutics

The Role of Adenosine Triphosphate and Adenosine Triphosphatase in the Release of Catecholamines from the Adrenal Medulla

III. Similarities between the Effects of Adenosine Triphosphate on Chromaffin Granules and on Mitochondria

¹ Department of Pharmacology, University of Kansas Medical Center, Kansas City, Kansas 66103, and Department of Pharmacology, McGill University, Montreal, Quebec, Canada

Further studies on the effect of ATP on chromaffin granules isolated from bovine adrenal medullae have been carried out. Granules isolated by density gradient centrifugation in an isotonic medium respond to ATP in the same way as do those isolated by Millipore filtration: release of catecholamines and fall in optical density. The effect of ATP was present when the KCl in the incubation medium was replaced by LiCl or choline chloride, and when the MgCl₂ was replaced by CoCl₂. ITP also caused the release of catecholamines but was less active than ATP. Bovine serum albumin caused a slight potentiation of the effects of ATP. The response to ATP was reduced as the pH was raised above 7.0. These effects are discussed in relation to the effects of ATP on mitochondria.