Abstract:
It has been shown that CU 18-07, CU 18-09 and CU 18-13, the acyl aniline derivatives as well as CU 18-12 the acyl aminopyridine derivative reduced spontaneous contraction of isolated rabbit duodenum. This study was to investigate the effects of four synthetic compounds on the contractility of isolated rat aorta. The thoracic aortic strips were isolated from male Wistar rats (250-300g), denuded the endothelium layer and then suspended in an organ bath containing 15 ml Krebs-Henseleit solution. It was found that four synthetic compounds (1x10[superscript -5]M and 1X10[superscript -4]M) significantly potentiated the contractility induced by noradrenaline (NA, 1x10[superscript -6]M). However, CU 18-09 and CU 18-12 inhibited the contraction in aorta with endothelium layer. CU 18-07,CU 18-09 (1x10[superscript -5]M and 1X10[superscript -4]M) could suppress contraction induced by potassium chloride (KCl,40 mM). CU 18-12 and CU 18-13 at the concentration of 1x10[superscript -5]M potentiated the effects of KCl in inducing aortic contraction. However, at the concentration of 5X10[superscript -5]M or 1X10[superscript -4]M, these compounds elicited the inhibitory effects on KCl induced aortic contraction. Furthermore, the four compounds significantly inhibited the contraction induced by tetraethylammonium (TEA, 1x10[superscript -3]M) as well as suppressed CaCl2- induced contraction dose response curve. These four synthetic compounds suppressed an increase in the resting tone in aorta (IRT), and also inhibited the aortic contraction in Ca[superscript 2+] free Krebs-Henseleit solution which induced by NA (1x10[superscript -6]M) and caffeine (1x10[superscript -6]M).The results from these experiments suggested that these four synthetic compounds interfered the entry of Ca[superscript 2+] into intracellular space via voltage operated calcium channel (VOC) and partly interfered the intracellular Ca[superscript 2+] mobilization. Moreover, these compounds might also influence the aortic contraction through mechanism involving endothelium layer