FEMS MicrobiologyLetters 95 ( 19921267-270 :i.~ 1992 Federation of Eun)pean Microbiological~cieties 0378-1097/92/$05.110 Published by Elsevier 267 FEMSLE 1151111 Phospholipids of Trypanosoma cruzi: Increase of polyphosphoinositides and phosphatidic acid after cholinergic stimulation * E.E. Machado de Domenech, M. Garcia, M.N. Garrido and G. Racagni Departamento de Biologia Molecular. Facultad de Ciencias Exactas, F~ico-Qubnh'as y Naturales. Unicer~idad Nacional de Rio CuarUJ. (~;rdoha. Argentina Received 211 April 1992 Revision received and accepted 1 June I9tJ2 Key words: Trypanosoma cruzi; Carbamoylcholine: Phosphatidic acid; Phosphatidylinositol; Cholinergic receptors 1. SUMMARY We have studied the effect of carbamoyl- choline in Trypanosoma cruzi epimastigote forms prelabelled with [32P]-Pi. Suspensions of cells were incubated at 28°C to measure changes in the levels of [32P]-Iabelled phospholipids after stimu- lation. The presence of this cholinergic agonist induced changes in the phosphoinositide metabo- lism; a shift in the levels of phosphatidylinositol 4,5-bisphosphate (PIP_,), phosphatidylinositol 4- phosphate (PIP) and phosphatidic acid (PA) was observed, whereas the levels of the other glyc- erophospholipids were not changed. This stud~ shows that carbamoylcholine either directly or Correspondence to." E.E. Machado de Domenech. Departa- mento de Biologla Molecular, Facultad de Ciencias Exactas. Fisico-Ou~micas y Naturales. Universidad Nacion:d de Rio Cuarto, 5800 Rio Cuarto, C6rdoba, Argentina. * A preliminary account of this work has been reported in ,I. Protozool. 42, Abstract (1991). indirectly influences changes in phosphoinositide metabolism. 2. INTRODUCTION In many biological systems, alteration in inosi- tolphospholipid metabolism occur~ .as the result of receptor occupancy by hormones, neurotrans- mitters or drugs. Early attention towards inositol phospholipid metabolism resulted from the work of Hokin and Hokin [1]. They showed that acetyl- choline stimulated [32p]-Iabelling of phosphatidic acid and phosphatidylinositol (PI) in the pan- creas. In the parotid, carbamoylcholine and iso- proterenol lead to activation of phosphoinositide- specific phospholipase and triglycerolipase re- spectively, and also, to the activation of many other enzyme-catalyzed reactions involved in dia- cylglycerol (DAG) turnover [2,3]. DAG is the physiological activator of protein kinase C (PKC), a regulator of cell proliferation and differentia- Downloaded from https://academic.oup.com/femsle/article/95/2-3/267/514089 by guest on 07 November 2021