Summary
The effect of increases in extracellular calcium [Ca]0 and the calcium ionophore A23187 on choline uptake and phosphatidylcholine biosynthesis was assessed in isolated cardiac myocytes. The cells were obtained from 7-day old chick embryos and were maintained in culture. Choline uptake was examined using [methyl 3H] choline. A23187 was found to increase choline uptake through the saturable choline uptake process. Pulse chase experiments using [methyl 3H] choline showed that after a 2 h incubation with choline, about 85% of the label was recovered in phosphocholine with most of the rest in phospholipid and a small amount in CDP-choline and glycerol phosphocholine. Increases in [Ca]0 up to 10 mM did not affect the amount of label in phosphocholine or phospholipid, the rate of disappearance of label from phosphocholine, or the rate of appearance of labelled choline in phospholipid. In contrast, A23187, at concentrations up to 10−4 M, was associated with a significant (p<0.05) increase in choline in the phosphocholine and phospholipid pool compared to control cells. The time course of the disappearance of choline from the phosphocholine pool and appearance in phospholipid pool was not significantly different between control cells and those treated with A23187. A23187 increased choline uptake via the specific uptake process. The effect on choline uptake may be attributed to the action of A23187 to facilitate the release of calcium from specific intracellular calcium storage sites rather than a nonspecific increase in [Ca]1 that may have resulted from the increase in [Ca]0.
This is a preview of subscription content, log in via an institution to check access.
Similar content being viewed by others
References
Ansell GB, Hawthorne JN, Dawson RMC (1973) Form and function of phospholipid. Elsevier Scientific Publc Co, Amsterdam
Bosteels S, Vleugels A, Carmeliet E (1970) Choline permeability in cardiac muscle cells of the cat. J Gen Physiol 55:602–619
Bradford M (1976) A rapid and sensitive method of quantitation of microgion quantitics of protein utilizing the principle of protein binding. Anal Biochem 72:248–253
DeHaan RL (1967) Regulation of spontaneous activity and growth of embryonic chick heart cells in tissue culture. Develop Biol 16:216–240
Dils RR, Hubscher G (1961) Metabolism of phospholipids III. The effects of calcium ions on the incorporation of labelled choline into rat liver microsomes. Biochimica et Biophysica Acta 46:505–513
Fabiato A, Fabiato F (1978) Calcium-induced release of calcium from sarcoplasmic reticulum of skinned cells from adult human, dog, cat, rabbit, rat, and frog heart and from fetal and new-born rat ventricles. Ann NY Acad Sci 307:499–522
Filler DA, Weinhold PA (1980) Base exchange reactions of the phospholipids in cardiac membranes. Biochemica et Biophysica Acta 618:223–230
Goldstein JL, Brown MS (1974) Binding and degradation of low-density lipoprotein by cultured human fibroblasts. Comparison of cells from a normal subject and from a patient with homozygous familial hypercholesterolemia. J Biol Chem 249:5153–5162
Hainaut K, Desmedt JE (1974) Calcium ionophore A23187 potentiates twitch and intracellular calcium release in single muscle fibers. Nature 252:407–408
Katz AM (1986) Membrane structure. In: Fozzard HA, Jennings RB, Haber E, Katz AM, Morgan HE (eds) The heart and cardiovascular system. Raven Press N.Y. 1986, pp 101–109
Kennedy EP, Weiss SB (1956) The function of cytidyl coenzymes in the biosynthesis of phospholipids. J Biol Chem 222:193–213
Kondo N (1986) Electromechanical effects of A23187 on guinea pig ventricular muscle: a dual action of A23187. J Molec Cell Card 18:907–915
Murray JJ, Dobson JG, Reed PW (1985) Effect of divalent cation ionophore A23187 on cardiac contractile parameters. Am J Physiol 249:H1195-H1203
Murray JJ, Reed PW, Dobson JG (1985) Biochemical changes accompanying enhanced cardiac contractility by ionophore A23187. Am J Physiol 249:H1204-H1210
Oide M (1982) Uptake and metabolism of choline by the embryonic heart of the chick in vitro. Comp Biochem Physiol 72B:493–499
Pressman BC (1972) Carboxylic ionophores as mobile carriers for divalent ions. In: Mehlman MA, Hanson RW (eds) The role of membrane in metabolic regulation. Academic Press, New York, p. 149
Pressman BC, Fahim M (1982) Pharmacology and toxicology of the monovalent carboxylic ionophores. Ann Rev Pharm Toxicol 22:465–490
Pritchard PH, Vance DE (1981) Choline metabolism and phospholipid biosynthesis in cultured rat hepatocytes. Biochem 196:261–267
Rabkin SW, Sunga PS, Myrdall S (1987) The effect of EGF on chronotropic response in cardiac cells in culture. Biochem Biophys Res Commun 40:889–897
Smith SW, Weiss SB, Kennedy EP (1957) The enzymatic dephosphorylation of phosphatidic acids. J Biol Chem 228:915–922
Sunga P, Pritchard PH, Rabkin SW (1987) Effect of cAMP on choline uptake and metabolism in isolated chick hearts in culture. Biochem and Cell Biology 66:231–237
Vance DE (1985) Phospholipid metabolism in eucaryotes. In: Vance DE, Vance JE (eds) Biochemistry of lipids and membrane. The Benjamin Cummings Publ Co, pp 242–270
Zelinski TA, Savard JD, Man RYK, Choy PC (1980) Phosphatidylcholine biosynthesis in isolated hamster heart. J Biol Chem 255:11423–11428
Author information
Authors and Affiliations
Additional information
Supported in part by a grant from Canadian (British Columbia) Heart Foundation
Rights and permissions
About this article
Cite this article
Rabkin, S.W. The effect of calcium ions and the calcium ionophore A23187 on choline uptake and phosphatidylcholine biosynthesis in chick embryo hearts. Basic Res Cardiol 83, 664–671 (1988). https://doi.org/10.1007/BF01906961
Received:
Issue Date:
DOI: https://doi.org/10.1007/BF01906961