Ca2+ analysis in arteries of spontaneously hypertensive rats by proton-induced X-ray emission.

Numerous investigations have shown that Ca2+ plays an important role in the pathogenesis of hypertension. Intracellular Ca2+ measurements have been carried out with Ca(2+)-selective electrodes and the Quin 2 method. The present study used particle induced X-ray emission to investigate the Ca2+ distribution in arterial smooth muscle. This method correlates Ca2+ distribution with the morphological structure of the tissue. The Ca2+ content of the aortas and renal arteries was measured in 22 spontaneously hypertensive and 11 normotensive rats. The findings demonstrate significant Ca(2+)-elevation in the aortas of spontaneously hypertensive rats compared with the aortas of normotensive rats (3124.9 +/- 790.0 versus 2031 +/- 478 micrograms Ca2+/g; P < 0.05), whereas there was only a tendency to Ca2+ elevation in the renal arteries of spontaneously hypertensive rats compared with normotensive rats (3336.0 +/- 1798.0 versus 1533.2 +/- 1082.0 micrograms Ca2+/g; NS). The Ca2+ was mainly detected in the muscle containing tunica media.