ISSN:1018-1172    

DOI:10.1159/000158184

出版商:S. Karger AG    

年代:1979

数据来源: Karger

摘要:

Extracellular Na can be accurately partitioned into free and bound components; the latter component is directly related to the hydration and stiffness of the vascular wall. Cell Na can be similarly partitioned: [Na+]i is about 10 mM and the transmembrane gradient about 15:1 in a physiological medium. The transmembrane gradient remains constant over a wide range of change in [Na+]0· Although active Na transport is largely responsible for developing the transmembrane ion distribution pattern, the membrane potential depends mainly on movements of K+ and Cl-No certain direct role can be assigned to Na+ in short-term vasoconstriction, but an indirect role through the regulation of catecholamine release and uptake is now established. There is evidence that the entry of Na+ into cells plays a fundamental role in the protein-synthesizing activity of the vascular smooth muscle cell and is thereby involved in the longer term determination of peripheral vascular resistance

ISSN:1018-1172    

DOI:10.1159/000158185

出版商:S. Karger AG    

年代:1979

数据来源: Karger

摘要:

Vascular smooth muscle (VSM) cells from hypertensive and normotensive rat aortae and caudal arteries were isolated by enzymatic techniques, homogenized, and fractionated by differential pelleting. By these techniques, only mitochondria could be enriched more than fivefold in any one fraction. The other organelles were distributed heterogeneously in almost all fractions. Hypertensive smooth muscle enzyme distribution patterns were different from the normotensive, suggesting that changes in sedimentation characteristics had occurred. Activity of the enzyme 5’-nucleotidase increased in whole tissue homogenates and in the ‘microsomal’ fraction of aortic and caudal artery of hypertensive VSM. The lysosomal protease, cathepsin D, of hypertensive animals decreased in activity for both vascular smooth muscles while N-acetyl-β-glucosaminidase and pNPPase (acid phosphatase) increased. The possibility of a functional deficiency in protein degradation causing lysosomal overloading is dis

ISSN:1018-1172    

DOI:10.1159/000158186

出版商:S. Karger AG    

年代:1979

数据来源: Karger

摘要:

A calcium-sensitive actomyosin was prepared from bovine aortic muscularis. The results of applying filament displacement tests indicate that bovine arterial actomyosin possesses predominantly a calcium regulatory system associated with the myosin filament, but also may possess a calcium regulatory system associated with the actin filament. Calcium binding to highly purified myosin preparations could not account for the calcium binding to calcium-sensitive actomyosin. A calcium-insensitive actomyosin preparation, prepared by omitting dithiothreitol from the isolation procedure, showed a definite loss of tropomyosin but no change in calcium binding relative to the calcium-sensitive actomyosin.

ISSN:1018-1172    

DOI:10.1159/000158187

出版商:S. Karger AG    

年代:1979

数据来源: Karger

摘要:

Platelet adherence in bovine endothelial cultures was studied by scanning and transmission electron microscopy. Following incubation with platelet-rich plasma (PRP), platelet adherence to endothelial cell surfaces was rare as compared to similarly-tested fibroblasts which displayed numerous adherent platelets. When endothelial cells were induced to retract from their substrate by exposure to cold or versene and then incubated with PRP, platelets were observed adhering to endothelial cell processes and to an extracellular microfilamentous network, located beneath the cell. Platelets were attached singly, retained their discoidal shape, and showed no evidence of granule release. In contrast, microfilaments and adherent platelets were conspicuously absent in endothelial cultures which were retracted with trypsin or collagenase and incubated with PRP. These preliminary results suggest that the observed interaction between platelets and the subcellular surface of cultured endothelial cells is specific for an extracellular network of microfilaments produced by the cells.

ISSN:1018-1172    

DOI:10.1159/000158188

出版商:S. Karger AG    

年代:1979

数据来源: Karger

摘要:

Geometric measurements were made of the nuclei of the muscle cells of the tunica media of human intracranial arteries. The nuclei measured 37 ± (SD) 6.4 µm in length, and 2.0 ± (SD) 0.83 µm average width and have a number density of 105 nuclei/mm3 (number per unit volume of tunica media). From the work of others it was known that the nuclei are centrally located within the cytoplasm of the muscle cell; because of this we have used the nuclei as indicators of alignment of the muscle cells themselves, making measurements from light micrographs of arterial sections stained with haematoxylin and eosin. On average, the nuclei were oriented at an angle that was not significantly different from a zero-degree pitch for the five sections analyzed in det

ISSN:1018-1172    

DOI:10.1159/000158189

出版商:S. Karger AG    

年代:1979

数据来源: Karger

摘要:

The effects of 7-oxa-13-prostynoic acid (7-OPA), alone and as an antagonist of PGE2 and PGF2α, were investigated in isolated rabbit aortic and canine renal arterial (diameter ∼0.5 mm) strips. 7-OPA caused contractions in both preparations; threshold concentrations were 3-to 10-fold higher than the PGs and maximum contraction was 50-60%. In concentrations of 10–5 M, 7-OPA inhibited contractions by PGF2α and PGE2. The same concentration of 7-OPA did not inhibit norepinephrine-induced contractions. These data indicate that 7-OPA is a partial agonist of PG receptors and produces its antagonism of PGE2 and PGF2α by that mec

ISSN:1018-1172    

DOI:10.1159/000158190

出版商:S. Karger AG    

年代:1979

数据来源: Karger

ISSN:1018-1172    

DOI:10.1159/000158191

出版商:S. Karger AG    

年代:1979

数据来源: Karger