Electron Microscopy and Electron Probe Analysis of Mitochondrial Cation Accumulation in Smooth Muscle

Abstract

The contractile responses to barium and the ultrastructure and ionic composition of mitochondria were studied in vascular smooth muscle . In normal rabbit portal anterior mesenteric vein (PAMV) and main pulmonary artery (MPA) smooth muscle mitochondria were frequently associated with the surface vesicles . The Electron probe X-ray microanalysis also showed a highly significant (P < 0 .001) correlation of P with mitochondrial Ba, in an estimated elemental ratio of approximately 3 Ba/4 P . Mitochondrial granules were still prominent after block staining of the osmium-fixed, Ba-loaded PAMV, but electron probe microanalysis showed no Ba, but only U, emissions . Tissues incubated with strontium had electron-opaque mitochondrial granules and deposits in the sarcoplasmic reticulum . X-ray microanalysis of mitochondria containing granules showed the presence of characteristic Sr and Ca emissions . The presence of Sr was similarly verified in the sarcoplasmic reticulum . These findings indicate the energy dependent uptake of divalent cations, in association with phosphate, by mitochondria in vascular smooth muscle in situ and the possibility that mitochondria may contribute to the regulation of intracellular divalent cation levels in smooth muscle .

Effects of Papaverine, Benactyzine and D600 on Ca2+ efflux, determined by means of a Ca2+-selective electrode, from guinea pig taenia coli into a Ca2+-free physiological solution.

“…Intracellular organelles such as sar coplasmic reticulum and mitocondria, cyto plasm and plasma membrane have been usually accepted as Ca locations in smooth muscle cells (15)(16)(17).…”

Smooth and Cardiac Muscle-selective Knock-out of Krüppel-like Factor 4 Causes Postnatal Death and Growth Retardation

“…The hearts were perfused through the aorta with 2% glutaraldehyde and kept in 2% glutaraldehyde overnight at 4°C. Small pieces (ϳ1-mm in diameter) of the lower left ventricle were then postfixed, stained, and embedded following the standard procedure (18,19): 2% osmium tetroxide for 2 h, saturated aqueous uranyl acetate for 1.5 h, dehydrated in a series of graded alcohols, and embedded in Spurr's resin. Sections were poststained by lead citrate and imaged in a Philips CM12 electron microscope at 120 KeV equipped with a SIA 8C 2,000 ϫ 3,000 CCD camera (Duluth, GA).…”

Decrease in Respiratory Function and Electron Transport Chain Induced by Airborne Particulate Matter (PM10) Exposure in Lung Mitochondria

“…Additionally, we performed some experiments using titanium dioxide nanoparticles (crystallite anatase size is in the sub-10 nm range) to investigate whether the mitochondrial exposure to particles induced the same response, but we found that titanium dioxide nanoparticles did not induce the same alterations in mitochondrial function even if the RCI decreases in the same magnitude. First, we observed alterations in mitochondria after PM 10 exposure, including unpacked and disrupted cristae with a decrease in parallel alignment and decrease in mitochondrial dense granules, which has been reported as calcium granules observed by TEM (Somlyo et al 1974). Structural abnormalities are strongly associated with metabolic changes, as reported here, for example, disruption in membrane integrity affected RCI in isolated mitochondrial from endotoxin-induced liver damage (Crouser et al 2002).…”