Molecular Pharmacology, Vol 5, 424-427, Copyright © 1969 by the American Society for Pharmacology and Experimental Therapeutics

The Effect of Ca⁺⁺ Omission on the Secretion of Catecholamines and the Incorporation of Orthophosphate-³²P into Nucleotides and Phospholipids of Bovine Adrenal Medulla during Acetylcholine Stimulation

¹ Department of Pharmacology and Therapeutics, McGill University, Montreal, Canada

Bovine adrenal medullary slices were incubated at 30° in Locke’s solution containing orthophosphate-³²P (50 µCi/ml) with and without Ca⁺⁺, and were stimulated with acetylcholine (10^-5 M) in the presence of eserine (10^-5 M).

The omission of Ca⁺⁺, as expected, abolished the increment in catecholamine secretion due to acetylcholine stimulation.

Acetylcholine stimulation increased the incorporation of ³²P into phospholipids, particularly into phosphatidic acid and into phosphatidylinositol, in both the presence and absence of Ca⁺⁺. Thus, a lack of correlation between catecholamine release and ³²P incorporation into phospholipids upon acetylcholine stimulation was observed.

Note:
ACKNOWLEDGMENTS I wish to thank Dr. A. Tenenhouse for reading the manuscript. Highly competent technical assistance was rendered by Mr. S. Iu.