ABSTRACT
The most sophisticated morphological approach depends upon rapid freezing of smooth muscle followed by sectioning and measurement of calcium (Ca) by X-ray microprobe analysis. Regulation of cytoplasmic Ca2+ concentration is a major determinant in the control of the contractile state of the vascular muscle. The use of isolated and purified plasma membranes from the vascular muscle may circumvent some of the difficulties inherent to the intact tissue preparation, thus allowing better characterization of the various modes of Ca membrane interactions. In earlier studies, large elastic arteries such as aorta have been commonly used, presumably due to their size so that the vascular muscle could be isolated and collected with reasonable ease and quantity. The multiplicity of membrane abnormalities provides a reasonable working hypothesis toward the understanding of several putative functional mechanisms postulated by a variety of investigators to account for the initiation and pathogenesis of hypertension.
