Abstract

L-serine decreases mean arterial pressure (MAP) in both normotensive and hypertensive rats. However, the molecular mechanism is not clear. Therefore, we examined the effect of L-serine on intracellular calcium (Ca2+) in cultured aortic vascular smooth muscle cells (VSMC) isolated from normotensive and hypertensive rat models. Ca2+ fluorescence intensity was studied by using confocal imaging. L-serine evoked a concentration dependent (5-30 µM) decrease in basal Ca2+ fluorescence intensity in normotensive rat models. This decrease in basal Ca2+ fluorescence intensity level was also profound in hypertensive rat models despite the fact that basal Ca2+ fluorescence intensity was higher in these models compared to the normotensive rats. We also observed L-serine (20-30 µM) decreases nuclear Ca2+ fluorescence intensity in both the rat models. In presence of a neutral amino acid transporter inhibitor, 2-amino-2-norbornane-carboxylic acid (BCH), L-serine did not have any effect on basal Ca2+ fluorescence intensity in VSMC of either rat models, suggesting the inhibition of amino acid transporter blocked the entry of L-serine in to the cell to have an effect. Hence this data indicates the possible role of L-serine in regulation of intracellular Ca2+ in these rat models.