TLC CHARACTERIZATION OF LIPOSOMES CONTAINING ANGIOTENSINOGEN, ANGIOTENSINE-I, ANGIOTENSINE-II AND SARALAZIN

Recent studies have described intracellular binding sites for angioten sine II. In vascular smooth muscle it was found that intracellular inj ection of angiotensin II increases the Ca2+ level. An alternative meth od for intracellular delivery of drugs is represented by using liposom es. Thus, the aim of this study was to characterize liposomes filled w ith angiotensinogen, angiotensine I (Ang I), angiotensine II (Ang II), and saralasin by a TLC method and examine the physiological effects o f these on rat vascular smooth muscle. Ang II (for all concentrations tested in the aqueous phase) and Ang I (for concentrations less than 1 0(-4)M) did not affect the thin-layer chromatography migration of this type of vesicle, suggesting that dose-dependent effects on physio-pha rmacological experiments could be studied. On the other hand, this typ e of experiment could not be performed for salarasin- or angiotensinog en-filled liposomes. Administration of liposomes containing Ang II (10 (-6)M), Ang I (10(-6)M), angiotensinogen (10(-6)M) and saralasine (10( -6)M) caused the contraction to isolated mt aorta smooth muscle, sugge sting the presence of active intracellular binding sites. (C) 1997 by John Wiley & Sons, Ltd.